Cash Trust Series N-CSRS Certified semi-annual shareholder report (management investment company)

United States

Securities and Exchange Commission

Washington, D.C. 20549

Form N-CSR

Certified Shareholder Report of Registered Management Investment Companies

811-5843

(Investment Company Act File Number)

Cash Trust Series, Inc.

______________________________________________________________

(Exact Name of Registrant as Specified in Charter)

Federated Investors Funds

4000 Ericsson Drive

Warrendale, PA 15086-7561

(Address of Principal Executive Offices)

(412) 288-1900

(Registrant's Telephone Number)

John W. McGonigle, Esquire

Federated Investors Tower

1001 Liberty Avenue

Pittsburgh, Pennsylvania 15222-3779

(Name and Address of Agent for Service)

(Notices should be sent to the Agent for Service)

Date of Fiscal Year End: 05/31/16

Date of Reporting Period: Six months ended 11/30/15

Item 1. Reports to Stockholders

Semi-Annual Shareholder Report

November 30, 2015

Ticker CTGXX

Federated Government Cash Series

A Portfolio of Cash Trust Series, Inc.

Not FDIC Insured
May Lose Value

No Bank Guarantee

CONTENTS

Portfolio of Investments Summary Tables	1
Portfolio of Investments	2
Financial Highlights	4
Statement of Assets and Liabilities	5
Statement of Operations	6
Statement of Changes in Net Assets	7
Notes to Financial Statements	8
Shareholder Expense Example	13
Evaluation and Approval of Advisory Contract	14
Voting Proxies on Fund Portfolio Securities	20
Quarterly Portfolio Schedule	20

Portfolio of Investments Summary Tables (unaudited)

At November 30, 2015, the Fund's portfolio composition¹ was as follows:

Portfolio Composition	Percentage of Total Net Assets
U.S. Government Agency Securities	13.0%
Repurchase Agreements	87.1%
Other Assets and Liabilities—Net2	(0.1)%
TOTAL	100.0%

At November 30, 2015, the Fund's effective maturity³ schedule was as follows:

Securities With an Effective Maturity of:	Percentage of Total Net Assets
1-7 Days	90.2%
8-30 Days	3.6%
31-90 Days	2.9%
91-180 Days	3.2%
181 Days or more	0.2%
Other Assets and Liabilities—Net2	(0.1)%
TOTAL	100.0%

1	See the Fund's Prospectus and Statement of Additional Information for a description of the principal types of securities in which the Fund invests.
2	Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.
3	Effective maturity is determined in accordance with the requirements of Rule 2a-7 under the Investment Company Act of 1940, which regulates money market mutual funds.

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Portfolio of Investments

November 30, 2015 (unaudited)

Principal Amount or Shares			Value
		GOVERNMENT AGENCIES—13.0%
$1,000,000	1	Federal Farm Credit System Discount Notes, 0.270%, 4/4/2016	$999,062
18,033,000	2	Federal Farm Credit System Floating Rate Notes, 0.172% - 0.222%, 12/1/2015 - 12/8/2015	18,032,812
17,000,000	2	Federal Home Loan Bank System Floating Rate Notes, 0.232% - 0.262%, 12/9/2015 - 1/27/2016	16,999,878
10,500,000		Federal Home Loan Bank System, 0.240% - 0.410%, 12/18/2015 - 7/13/2016	10,499,279
2,500,000	2	Federal Home Loan Mortgage Corp. Floating Rate Notes, 0.201%, 12/12/2015	2,499,715
4,946,000		Federal National Mortgage Association, 0.500%, 3/15/2016 - 3/30/2016	4,961,634
		TOTAL GOVERNMENT AGENCIES	53,992,380
		REPURCHASE AGREEMENTS—87.1%
3,000,000	3	Interest in $250,000,000 joint repurchase agreement 0.22%, dated 3/5/2015 under which Bank of Nova Scotia will repurchase securities provided as collateral for $250,414,028 on 12/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency securities with various maturities to 7/20/2062 and the market value of those underlying securities was $256,113,976.	3,000,000
80,619,000		Interest in $4,000,000,000 joint repurchase agreement 0.10%, dated 11/30/2015 under which Credit Agricole CIB New York will repurchase securities provided as collateral for $4,000,011,111 on 12/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 11/15/2045 and the market value of those underlying securities was $4,080,011,398.	80,619,000
100,000,000		Interest in $500,000,000 joint repurchase agreement 0.13%, dated 11/30/2015 under which Mizuho Securities USA, Inc. will repurchase securities provided as collateral for $500,001,806 on 12/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency securities with various maturities to 12/25/2049 and the market value of those underlying securities was $512,215,106.	100,000,000
80,000,000		Interest in $100,000,000 joint repurchase agreement 0.13%, dated 11/30/2015 under which Pershing LLC will repurchase securities provided as collateral for $100,000,361 on 12/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency securities and a U.S. Treasury security with various maturities to 10/20/2065 and the market value of those underlying securities was $102,410,287.	80,000,000

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Principal Amount or Shares		Value
	REPURCHASE AGREEMENTS—continued
$100,000,000	Interest in $250,000,000 joint repurchase agreement 0.11%, dated 11/30/2015 under which Royal Bank of Scotland will repurchase securities provided as collateral for $250,000,764 on 12/1/2015. The securities provided as collateral at the end of the period held with JPMorgan Chase as tri-party agent, were U.S. Treasury securities with various maturities to 2/15/2040 and the market value of those underlying securities was $255,002,102.	$100,000,000
	TOTAL REPURCHASE AGREEMENTS (AT COST)	363,619,000
	TOTAL INVESTMENTS—100.1% (AT AMORTIZED COST)4	417,611,380
	OTHER ASSETS AND LIABILITIES - NET—(0.1)%5	(235,942)
	TOTAL NET ASSETS—100%	$417,375,438

1	Discount rate(s) at time of purchase.
2	Floating rate notes with current rate(s) and next reset date(s) shown.
3	Although the repurchase date is more than seven days after the date of purchase, the Fund has the right to terminate the repurchase agreement at any time with seven-days' notice.
4	Also represents cost for federal tax purposes.
5	Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.

Note: The categories of investments are shown as a percentage of total net assets at November 30, 2015.

Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below:

Level 1—quoted prices in active markets for identical securities.

Level 2—other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.). Also includes securities valued at amortized cost.

Level 3—significant unobservable inputs (including the Fund's own assumptions in determining the fair value of investments).

The inputs or methodology used for valuing securities are not an indication of the risk associated with investing in those securities.

As of November 30, 2015, all investments of the Fund are valued at amortized cost, which is considered a Level 2 input, in valuing the Fund's assets.

The following acronym is used throughout this portfolio:

LLC —Limited Liability Corporation

See Notes which are an integral part of the Financial Statements

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Financial Highlights

(For a Share Outstanding Throughout Each Period)

	Six Months Ended (unaudited) 11/30/2015	Year Ended May 31,
		2015	2014	2013	2012	2011
Net Asset Value, Beginning of Period	$1.00	$1.00	$1.00	$1.00	$1.00	$1.00
Income From Investment Operations:
Net investment income	0.00001	0.00001	0.0001	0.0001	0.0001	0.0001
Net realized gain on investments	0.0001	0.00001	0.00001	0.00001	0.00001	0.00001
TOTAL FROM INVESTMENT OPERATIONS	0.0001	0.00001	0.0001	0.0001	0.0001	0.0001
Less Distributions:
Distributions from net investment income	(0.0001)	(0.0000)1	(0.0001)	(0.0001)	(0.0001)	(0.0001)
Distributions from net realized gain on investments	(0.0000)1	(0.0000)1	(0.0000)1	(0.0000)1	(0.0000)1	(0.0000)1
TOTAL DISTRIBUTIONS	(0.0001)	(0.0000)1	(0.0001)	(0.0001)	(0.0001)	(0.0001)
Net Asset Value, End of Period	$1.00	$1.00	$1.00	$1.00	$1.00	$1.00
Total Return2	0.01%	0.01%	0.01%	0.01%	0.01%	0.01%
Ratios to Average Net Assets:
Net expenses	0.12%3	0.09%	0.09%	0.18%	0.16%	0.23%
Net investment income	0.01%3	0.01%	0.01%	0.01%	0.01%	0.01%
Expense waiver/reimbursement4	0.97%3	0.98%	0.97%	0.88%	0.90%	0.84%
Supplemental Data:
Net assets, end of period (000 omitted)	$417,375	$498,580	$2,470,320	$2,504,174	$2,557,022	$2,522,787

1	Represents less than $0.0001.
2	Based on net asset value. Total returns for periods of less than one year are not annualized.
3	Computed on an annualized basis.
4	This expense decrease is reflected in both the net expense and the net investment income ratios shown above.

See Notes which are an integral part of the Financial Statements

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Statement of Assets and Liabilities

November 30, 2015 (unaudited)

Assets:
Investment in repurchase agreements	$363,619,000
Investment in securities	53,992,380
Total investment in securities, at amortized cost and fair value		$417,611,380
Income receivable		38,787
Receivable for shares sold		100
TOTAL ASSETS		417,650,267
Liabilities:
Payable for shares redeemed	4,743
Bank overdraft	145,200
Payable to adviser (Note 4)	31,320
Payable for custodian fees	5,618
Payable for transfer agent fee	33,186
Payable for Directors'/Trustees' fees (Note 4)	263
Payable for portfolio accounting fees	27,246
Payable for share registration costs	6,478
Payable for printing and postage	7,619
Accrued expenses (Note 4)	13,156
TOTAL LIABILITIES		274,829
Net assets for 417,375,436 shares outstanding		$417,375,438
Net Assets Consist of:
Paid-in capital		$417,375,436
Undistributed net investment income		2
TOTAL NET ASSETS		$417,375,438
Net Asset Value, Offering Price and Redemption Proceeds Per Share:
$417,375,438 ÷ 417,375,436 shares outstanding, no par value, unlimited shares authorized		$1.00

See Notes which are an integral part of the Financial Statements

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Statement of Operations

Six Months Ended November 30, 2015 (unaudited)

Investment Income:
Interest			$309,622
Expenses:
Investment adviser fee (Note 4)		$1,170,077
Administrative fee (Note 4)		183,201
Custodian fees		9,826
Transfer agent fee		229,242
Directors'/Trustees' fees (Note 4)		761
Auditing fees		24,638
Legal fees		11,584
Portfolio accounting fees		57,775
Distribution services fee (Note 4)		234,016
Other service fees (Notes 2 and 4)		585,039
Share registration costs		13,012
Printing and postage		44,285
Taxes		1,525
Miscellaneous (Note 4)		12,497
TOTAL EXPENSES		2,577,478
Waivers and Reimbursement:
Waiver of investment adviser fee (Note 4)	$(1,170,077)
Waivers/reimbursements of other operating expenses (Notes 2 and 5)	(1,120,957)
TOTAL WAIVERS AND REIMBURSEMENT		(2,291,034)
Net expenses			286,444
Net investment income			23,178
Net realized gain on investments			1,105
Change in net assets resulting from operations			$24,283

See Notes which are an integral part of the Financial Statements

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Statement of Changes in Net Assets

	Six Months Ended (unaudited) 11/30/2015	Year Ended 5/31/2015
Increase (Decrease) in Net Assets
Operations:
Net investment income	$23,178	$149,859
Net realized gain on investments	1,105	31,897
CHANGE IN NET ASSETS RESULTING FROM OPERATIONS	24,283	181,756
Distributions to Shareholders:
Distributions from net investment income	(23,507)	(149,910)
Distributions from net realized gain on investments	(32,457)	(545)
CHANGE IN NET ASSETS RESULTING FROM DISTRIBUTIONS TO SHAREHOLDERS	(55,964)	(150,455)
Share Transactions:
Proceeds from sale of shares	441,213,970	1,513,857,991
Net asset value of shares issued to shareholders in payment of distributions declared	55,142	150,291
Cost of shares redeemed	(522,442,240)	(3,485,779,783)
CHANGE IN NET ASSETS RESULTING FROM SHARE TRANSACTIONS	(81,173,128)	(1,971,771,501)
Change in net assets	(81,204,809)	(1,971,740,200)
Net Assets:
Beginning of period	498,580,247	2,470,320,447
End of period (including undistributed net investment income of $2 and $331, respectively)	$417,375,438	$498,580,247

See Notes which are an integral part of the Financial Statements

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Notes to Financial Statements

November 30, 2015 (unaudited)

1. ORGANIZATION

Cash Trust Series, Inc. (the “Corporation”) is registered under the Investment Company Act of 1940, as amended (the “Act”), as an open-end management investment company. The Corporation consists of four portfolios. The financial statements included herein are only those of Federated Government Cash Series (the “Fund”), a diversified portfolio. The financial statements of the other portfolios are presented separately. The assets of each portfolio are segregated and a shareholder's interest is limited to the portfolio in which shares are held. Each portfolio pays its own expenses. The primary investment objective of the Fund is current income consistent with stability of principal and liquidity.

2. SIGNIFICANT ACCOUNTING POLICIES

The following is a summary of significant accounting policies consistently followed by the Fund in the preparation of its financial statements. These policies are in conformity with U.S. generally accepted accounting principles (GAAP).

Investment Valuation

Securities are valued at amortized cost. Under the amortized cost valuation method, an investment is valued initially at its cost as determined in accordance with GAAP. The Fund then adjusts the amount of interest income accrued each day over the term of the investment to account for any difference between the initial cost of the investment and the amount payable at its maturity. If amortized cost is determined not to approximate fair value, the value of the portfolio securities will be determined in accordance with the procedures described below.

The Directors have ultimate responsibility for determining the fair value of investments. The Directors have appointed a valuation committee (“Valuation Committee”) comprised of officers of the Fund, Federated Investment Management Company (“Adviser”) and certain of the Adviser's affiliated companies to assist in determining fair value of securities and in overseeing the comparison of amortized cost to market-based value. The Directors have also authorized the use of pricing services recommended by the Valuation Committee to provide fair value evaluations of the current value of certain investments for purposes of monitoring the relationship of market-based value and amortized cost. The Valuation Committee employs various methods for reviewing third-party pricing-service evaluations including periodic reviews of third-party pricing services' policies, procedures and valuation methods (including key inputs and assumptions), and review of price challenges by the Adviser based on recent market activity. In the event that market quotations and price evaluations are not available for an investment, the Valuation Committee determines the fair value of the investment in accordance with procedures adopted by the Directors. The Directors periodically review and approve the fair valuations made by the Valuation Committee and any changes made to the procedures.

Repurchase Agreements

The Fund may invest in repurchase agreements for short-term liquidity purposes. It is the policy of the Fund to require the other party to a repurchase agreement to transfer to the Fund's custodian or sub-custodian eligible securities or cash with a market value (after transaction costs) at least equal to the repurchase price to be paid under the repurchase

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agreement. The eligible securities are transferred to accounts with the custodian or sub-custodian in which the Fund holds a “securities entitlement” and exercises “control” as those terms are defined in the Uniform Commercial Code. The Fund has established procedures for monitoring the market value of the transferred securities and requiring the transfer of additional eligible securities if necessary to equal at least the repurchase price. These procedures also allow the other party to require securities to be transferred from the account to the extent that their market value exceeds the repurchase price or in exchange for other eligible securities of equivalent market value.

The insolvency of the other party or other failure to repurchase the securities may delay the disposition of the underlying securities or cause the Fund to receive less than the full repurchase price. Under the terms of the repurchase agreement, any amounts received by the Fund in excess of the repurchase price and related transaction costs must be remitted to the other party.

The Fund may enter into repurchase agreements in which eligible securities are transferred into joint trading accounts maintained by the custodian or sub-custodian for investment companies and other clients advised by the Fund's Adviser and its affiliates. The Fund will participate on a pro rata basis with the other investment companies and clients in its share of the securities transferred under such repurchase agreements and in its share of proceeds from any repurchase or other disposition of such securities.

Repurchase agreements are subject to Master Netting Agreements which are agreements between the Fund and its counterparties that provide for the net settlement of all transactions and collateral with the Fund, through a single payment, in the event of default or termination. Amounts presented on the Portfolio of Investments and Statement of Assets and Liabilities are not net settlement amounts but gross. As indicated above, the cash or securities to be repurchased, as shown on the Portfolio of Investments, exceeds the repurchase price to be paid under the agreement reducing the net settlement amount to zero.

Investment Income, Gains and Losses, Expenses and Distributions

Investment transactions are accounted for on a trade-date basis. Realized gains and losses from investment transactions are recorded on an identified-cost basis. Interest income and expenses are accrued daily. Distributions to shareholders are recorded on the ex-dividend date. Distributions of net investment income are declared daily and paid monthly.

For the six months ended November 30, 2015, unaffiliated third parties waived $211,168 of transfer agent fees.

Dividends are declared separately for each class. No class has preferential dividend rights; differences in per share dividend rates are generally due to differences in separate class expenses.

Other Service Fees

The Fund may pay other service fees up to 0.25% of the average daily net assets of the Fund's shares to unaffiliated financial intermediaries or to Federated Shareholder Services Company (FSSC) for providing services to shareholders and maintaining shareholder accounts. Subject to the terms described in the Expense Limitation note, FSSC may voluntarily reimburse the Fund for other service fees. For the six months ended November 30, 2015, unaffiliated third-party financial intermediaries waived $585,039 of other services. This waiver can be modified or terminated at any time.

Premium and Discount Amortization

All premiums and discounts are amortized/accreted using the effective-interest-rate method.

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Federal Taxes

It is the Fund's policy to comply with the Subchapter M provision of the Internal Revenue Code and to distribute to shareholders each year substantially all of its income. Accordingly, no provision for federal income tax is necessary. As of and during the six months ended November 30, 2015, the Fund did not have a liability for any uncertain tax positions. The Fund recognizes interest and penalties, if any, related to tax liabilities as income tax expense in the Statement of Operations. As of November 30, 2015, tax years 2012 through 2015 remain subject to examination by the Fund's major tax jurisdictions, which include the United States of America and the state of Maryland, the Commonwealth of Pennsylvania.

Other Taxes

As an open-end management investment company incorporated in the state of Maryland but domiciled in the Commonwealth of Pennsylvania, the Fund is subject to the Pennsylvania Franchise Tax. This franchise tax is assessed annually on the value of the Fund, as represented by average net assets for the tax year.

When-Issued and Delayed-Delivery Transactions

The Fund may engage in when-issued or delayed-delivery transactions. The Fund records when-issued securities on the trade date and maintains security positions such that sufficient liquid assets will be available to make payment for the securities purchased. Securities purchased on a when-issued or delayed-delivery basis are marked to market daily and begin earning interest on the settlement date. Losses may occur on these transactions due to changes in market conditions or the failure of counterparties to perform under the contract.

Other

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts of assets, liabilities, expenses and revenues reported in the financial statements. Actual results could differ from those estimated. The Fund applies Investment Company accounting and reporting guidance.

3. CAPITAL STOCK

The following table summarizes capital stock activity:

	Six Months Ended 11/30/2015	Year Ended 5/31/2015
Shares sold	441,213,970	1,513,857,991
Shares issued to shareholders in payment of distributions declared	55,142	150,291
Shares redeemed	(522,442,240)	(3,485,779,783)
NET CHANGE RESULTING FROM FUND SHARE TRANSACTIONS	(81,173,128)	(1,971,771,501)

4. INVESTMENT ADVISER FEE AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Adviser Fee

The advisory agreement between the Fund and the Adviser provides for an annual fee equal to 0.50% of the Fund's average daily net assets. Subject to the terms described in the Expense Limitation note, the Adviser may voluntarily choose to waive any portion of its fee and/or reimburse certain operating expenses of the Fund. For the six months ended November 30, 2015, the Adviser voluntarily waived its entire fee of $1,170,077 and voluntarily reimbursed $90,734 of other operating expenses.

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Administrative Fee

Federated Administrative Services (FAS), under the Administrative Services Agreement, provides the Fund with administrative personnel and services. For purposes of determining the appropriate rate breakpoint, “Investment Complex” is defined as all of the Federated Funds subject to a fee under the Administrative Services Agreement. The fee paid to FAS is based on the average daily net assets of the Investment Complex as specified below, plus certain out-of-pocket expenses:

Administrative Fee	Average Daily Net Assets of the Investment Complex
0.150%	on the first $5 billion
0.125%	on the next $5 billion
0.100%	on the next $10 billion
0.075%	on assets in excess of $20 billion

Subject to the terms described in the Expense Limitation note, FAS may voluntarily choose to waive any portion of its fee. For the six months ended November 30, 2015, the annualized fee paid to FAS was 0.078% of average daily net assets of the Fund.

Distribution Services Fee

The Fund has adopted a Distribution Plan (the “Plan”) pursuant to Rule 12b-1 under the Act. Under the terms of the Plan, the Fund will reimburse Federated Securities Corp. (FSC), the principal distributor, from the daily net assets of the Fund to finance activities intended to result in the sale of these shares. The Plan provides that the Fund may incur distribution expenses of up to 0.35% of average daily net assets, annually, to reimburse FSC. Subject to the terms described in the Expense Limitation note, FSC may voluntarily choose to waive any portion of its fee. For the six months ended November 30, 2015, FSC voluntarily waived its entire fee of $234,016. When FSC receives fees, it may pay some or all of them to financial intermediaries whose customers purchase shares.

Expense Limitation

Due to the possibility of changes in market conditions and other factors, there can be no assurance that the level of waivers/reimbursement/reduction of Fund expenses reflected in the financial highlights will be maintained in the future. However, the Adviser and certain of its affiliates (which may include FSC, FAS and FSSC) on their own initiative, have agreed to waive certain amounts of their respective fees and/or reimburse expenses. Total annual fund operating expenses (as shown in the financial highlights, excluding extraordinary expenses and proxy-related expenses paid by the Fund, if any) paid by the Fund (after the voluntary waivers and/or reimbursements) will not exceed 1.05% (the “Fee Limit”), up to but not including the later of (the “Termination Date”): (a) August 1, 2016; or (b) the date of the Fund's next effective Prospectus. While the Adviser and its applicable affiliates currently do not anticipate terminating or increasing these arrangements prior to the Termination Date, these arrangements may only be terminated or the Fee Limit increased prior to the Termination Date with the agreement of the Directors.

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General

Certain Officers and Directors of the Fund are Officers and Directors or Trustees of certain of the above companies. To efficiently facilitate payment, Directors'/Trustees' fees and certain expenses related to conducting meetings of the Directors/Trustees and other miscellaneous expenses are paid by an affiliate of the Adviser which in due course are reimbursed by the Fund. Such expenses may be included in Accrued and Miscellaneous Expenses on the Statement of Assets and Liabilities and Statement of Operations, respectively.

5. LINE OF CREDIT

The Fund participates in a $100,000,000 unsecured, uncommitted revolving line of credit (LOC) agreement with PNC Bank. The LOC was made available for extraordinary or emergency purposes, primarily for financing redemption payments. Borrowings are charged interest at a rate offered to the Fund by PNC Bank at the time of the borrowing. As of November 30, 2015, there were no outstanding loans. During the six months ended November 30, 2015, the Fund did not utilize the LOC.

6. INTERFUND LENDING

Pursuant to an Exemptive Order issued by the Securities and Exchange Commission (SEC), the Fund, along with other funds advised by subsidiaries of Federated Investors, Inc., may participate in an interfund lending program. This program provides an alternative credit facility allowing the Fund to borrow from other participating affiliated funds. As of November 30, 2015, there were no outstanding loans. During the six months ended November 30, 2015, the program was not utilized.

7. regulatory matters

On July 23, 2014, the SEC voted to amend the rules under the Act which currently govern the operations of the Fund. A significant change resulting from these amendments will be a requirement that institutional prime funds (i.e. not government or retail as defined in the amendments), transact fund shares based on a market-based Net Asset Value (NAV). This change does not impact government money market funds, and because it is anticipated that the Fund will constitute a government money market fund under the new rules, the Fund will be permitted to continue transacting fund shares at an NAV calculated using the amortized cost valuation method. Among additional disclosure and other requirements, the amendments also will permit a money market fund, or, in certain circumstances, require a money market fund (other than a government money market fund, like the Fund, which satisfies the requirements of the amendments) to impose liquidity fees on redemptions, and permit a money market fund to limit (or gate) redemptions for up to 10 business days in any 90-day period. The amendments have staggered compliance dates. Compliance with a majority of these amendments will be required on October 14, 2016, two years after the effective date for the rule amendments. The degree to which a money market fund will be impacted by the rule amendments will depend upon the type of fund and type of investors (retail or institutional). At this time, management is evaluating the implications of these amendments and their impact to the Fund's operations, financial statements and accompanying notes.

8. SUBSEQUENT EVENTS

On December 11, 2015, Federated Government Obligations Fund acquired all or substantially all of the assets of the Fund in complete liquidation and termination of the Fund.

Management has evaluated subsequent events through the date the financial statements were issued and determined that no additional events occurred that require disclosure.

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Shareholder Expense Example (unaudited)

As a shareholder of the Fund, you incur ongoing costs, including management fees and to the extent applicable, distribution (12b-1) fees and/or other service fees and other Fund expenses. This Example is intended to help you to understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds. It is based on an investment of $1,000 invested at the beginning of the period and held for the entire period from June 1, 2015 to November 30, 2015.

ACTUAL EXPENSES

The first section of the table below provides information about actual account values and actual expenses. You may use the information in this section, together with the amount you invested, to estimate the expenses that you incurred over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number in the first section under the heading entitled “Expenses Paid During Period” to estimate the expenses attributable to your investment during this period.

HYPOTHETICAL EXAMPLE FOR COMPARISON PURPOSES

The second section of the table below provides information about hypothetical account values and hypothetical expenses based on the Fund's actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund's actual return. Thus, you should not use the hypothetical account values and expenses to estimate the actual ending account balance or your expenses for the period. Rather, these figures are required to be provided to enable you to compare the ongoing costs of investing in the Fund with other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

Please note that the expenses shown in the table are meant to highlight your ongoing costs only. Therefore, the second section of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds.

	Beginning Account Value 6/1/2015	Ending Account Value 11/30/2015	Expenses Paid During Period1,2
Actual	$1,000	$1,000.10	$0.60
Hypothetical (assuming a 5% return before expenses)	$1,000	$1,024.40	$0.61

1

Expenses are equal to the Fund's annualized net expense ratio of 0.12%, multiplied by the average account value over the period, multiplied by 183/366 (to reflect the one-half-year period).

2

Actual and Hypothetical expenses paid during the period utilizing the Fund's current Fee Limit of 1.05% (as reflected in the Notes to Financial Statements, Note 4 under Expense Limitation), multiplied by the average account value over the period, multiplied by 183/366 (to reflect expenses paid as if they had been in effect throughout the most recent one-half-year period) would be $5.25 and $5.30, respectively.

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Evaluation and Approval of Advisory Contract–May 2015

Federated Government Cash Series (the “Fund”)

Following a review and recommendation of approval by the Fund's independent directors, the Fund's Board reviewed and approved at its May 2015 meetings the Fund's investment advisory contract for an additional one-year term. The Board's decision regarding the contract reflects the exercise of its business judgment on whether to continue the existing arrangements.

In this connection, the Federated Funds' Board had previously appointed a Senior Officer, whose duties include specified responsibilities relating to the process by which advisory fees are to be charged to a Federated fund. The Senior Officer has the authority to retain consultants, experts, or staff as may be reasonably necessary to assist in the performance of his duties, reports directly to the Board, and may be terminated only with the approval of a majority of the independent members of the Board. The Senior Officer prepared and furnished to the Board an independent, written evaluation that covered topics discussed below (the “Evaluation”). The Board considered that Evaluation, along with other information, in deciding to approve the advisory contract.

The Board is also familiar with and considered judicial decisions concerning allegedly excessive investment advisory fees, which have indicated that the following factors may be relevant to an Adviser's fiduciary duty with respect to its receipt of compensation from a fund: the nature and quality of the services provided by the Adviser to a fund and its shareholders, including the performance and expenses of the fund and of comparable funds; the Adviser's cost of providing the services, including the profitability to the Adviser of providing advisory services to a fund; the extent to which the Adviser may realize “economies of scale” as a fund grows larger and, if such economies of scale exist, whether they have been shared with a fund and its shareholders or the family of funds; any “fall-out financial benefits” that accrue to the Adviser because of its relationship with a fund (including research services received from brokers that execute fund trades and any fees paid to affiliates of the Adviser for services rendered to a fund); comparative fee structures, including a comparison of fees paid to the Adviser with those paid by similar funds; and the extent of care, conscientiousness and independence with which the Board members perform their duties and their expertise, including whether they are fully informed about all facts the Board deems relevant to its consideration of the Adviser's services and fees. The Board noted that SEC disclosure requirements regarding the basis for the Board's approval of the Fund's advisory contract generally track the factors listed above. Consistent with these judicial decisions and SEC disclosure requirements, the Board also considered management fees

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charged to institutional and other clients of the Adviser for what might be viewed as like services. The Board was aware of these factors and was guided by them in its review of the Fund's advisory contract to the extent it considered them to be appropriate and relevant, as discussed further below.

The Board considered and weighed these circumstances in light of its substantial accumulated experience in governing the Fund and working with Federated on matters relating to the Federated funds, and was assisted in its deliberations by independent legal counsel. Throughout the year, and in connection with its May meetings, the Board requested and received substantial and detailed information about the Fund and the Federated organization that was in addition to the extensive materials that comprise and accompany the Senior Officer's Evaluation. Federated provided much of this information at each regular meeting of the Board, and furnished additional substantial information in connection with the May meeting at which the Board's formal review of the advisory contract occurred. At this May meeting, senior management of the Adviser also met with the independent directors and their counsel to discuss the materials presented and any other matters thought relevant by the Adviser or the directors. Between regularly scheduled meetings, the Board also received information on particular matters as the need arose. Thus, the Board's consideration of the advisory contract included review of the Senior Officer's Evaluation, accompanying data and additional information covering such matters as: the Adviser's investment philosophy, revenue, profitability, personnel and processes; investment and operating strategies; the Fund's short- and long-term performance (in absolute terms, both on a gross basis and net of expenses, as well as in relationship to its particular investment program and certain competitor or “peer group” funds and/or other benchmarks, as appropriate), and comments on the reasons for performance; the Fund's investment objectives; the Fund's expenses (including the advisory fee itself and the overall expense structure of the Fund, both in absolute terms and relative to similar and/or competing funds, with due regard for contractual or voluntary expense limitations); the use and allocation of brokerage commissions derived from trading the Fund's portfolio securities (if any); and the nature, quality and extent of the advisory and other services provided to the Fund by the Adviser and its affiliates. The Board also considered the preferences and expectations of Fund shareholders; the entrepreneurial risk assumed by the Adviser in sponsoring the funds; the continuing state of competition in the mutual fund industry and market practices; the range of comparable fees for similar funds in the mutual fund industry; the Fund's relationship to the Federated family of funds which include a comprehensive array of funds with different investment objectives, policies and strategies which are available for exchange without the incurrence of additional sales charges; compliance and audit reports concerning the Federated funds and the Federated companies that service them (including communications from regulatory agencies), as well as Federated's responses to any issues raised therein; and relevant developments in

Semi-Annual Shareholder Report

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the mutual fund industry and how the Federated funds and/or Federated are responding to them. The Board's evaluation process is evolutionary. The criteria considered and the emphasis placed on relevant criteria change in recognition of changing circumstances in the mutual fund marketplace.

While mindful that courts have cautioned against giving such comparisons too much weight, the Board has found the use of comparisons of the Fund's fees and expenses to other mutual funds with comparable investment programs to be relevant. In this regard, the Board was presented with, and considered, information regarding the contractual advisory fee rates, net advisory fee rates and total expense ratios relative to a fund's peers. The Board focused on comparisons with other similar mutual funds more heavily than non-mutual fund products or services because it is believed that they are more relevant. For example, other mutual funds are the products most like the Fund, they are readily available to Fund shareholders as alternative investment vehicles, and they are the type of investment vehicle in fact chosen and maintained by the Fund's investors. The range of their fees and expenses therefore appears to be a relevant indicator of what consumers have found to be reasonable in the precise marketplace in which the Fund competes.

It was noted in the materials for the Board meeting that for the period covered by the Evaluation, the Fund's investment advisory fee was waived in its entirety. The Board reviewed the contractual advisory fee rate, net advisory fee rate and other expenses of the Fund with the Adviser and noted the position of the Fund's fee rates relative to its peers. In this regard, the Board noted that the contractual advisory fee rate was above the median of the relevant peer group, but the Board noted that the investment advisory fee was waived in its entirety and that the overall expense structure of the Fund remained competitive.

By contrast, the Senior Officer has reviewed Federated's fees for providing advisory services to products outside the Federated family of funds (e.g., institutional and separate accounts and sub-adviser services). He concluded that mutual funds and institutional accounts are inherently different products. Those differences include, but are not limited to, different types of targeted investors; being subject to different laws and regulations; different legal structures; different average account sizes and portfolio management techniques made necessary by different cash flows and different associated costs; and the time spent by portfolio managers and their teams, funds financial services, legal, compliance and risk management in reviewing securities pricing, addressing different administrative responsibilities, addressing different degrees of risk associated with management and a variety of different costs. The Senior Officer did not consider these fee schedules to be determinative in judging the appropriateness of mutual fund advisory fees.

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The Fund's ability to deliver competitive performance when compared to its peer group was also deemed to be relevant by the Board as a useful indicator of how the Adviser is executing the Fund's investment program, which in turn was one of the Board's considerations in reaching a conclusion that the nature, extent, and quality of the Adviser's investment management services were such as to warrant continuation of the advisory contract.

The Senior Officer reviewed information compiled by Federated, using data supplied by independent fund ranking organizations, regarding the performance of, and fees charged by, other mutual funds, noting his view that comparisons to fund peer groups may be helpful, though not conclusive, in judging the reasonableness of the proposed fees. The Board considered, in evaluating such comparisons, that in some cases individual funds may exhibit significant and unique differences in their objectives and management techniques when compared to other funds within an industry peer group.

The Fund's performance was above the median of the relevant peer group for the one-year period covered by the Evaluation.

The Board also received financial information about Federated, including information regarding the compensation and benefits Federated derived from its relationships with the Federated funds. This information covered not only the fees under the advisory contracts, but also fees received by Federated's subsidiaries for providing other services to the Federated funds under separate contracts (e.g., for serving as the Federated funds' administrator). The information also detailed any indirect benefit Federated may derive from its receipt of research services from brokers who execute Federated fund trades. In addition, the Board considered the fact that, in order for a fund to be competitive in the marketplace, Federated and its affiliates frequently waived fees and/or reimbursed expenses and have disclosed to fund investors and/or indicated to the Board their intention to do so in the future, where appropriate. Moreover, the Board receives regular reporting as to the institution, adjustment or elimination of these voluntary waivers.

In addition, over the past two years, following discussions regarding the Senior Officer's recommendations, Federated made meaningful reductions to the contractual advisory fees for several Funds. In May 2014, the Senior Officer recommended that Federated review the fee structures of its money market funds to determine whether it would be appropriate to consider alternative pricing structures. Federated has combined that review with its consideration of the re-structuring of its money market fund product line in response to the recently adopted amendments to Rule 2a-7 under the Investment Company Act of 1940, as amended (the “1940 Act”).

At the Board meeting in May 2015, following previous recommendations of the Senior Officer, Federated proposed, and the Board approved, reductions in the contractual advisory fees of certain other Funds.

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Federated furnished information, requested by the Senior Officer, that reported revenues on a fund-by-fund basis and made estimates of the allocation of expenses on a fund-by-fund basis, using allocation methodologies specified by the Senior Officer. The Senior Officer noted that, while these cost allocation reports apply consistent allocation processes, the inherent difficulties in allocating costs continues to cause the Senior Officer to question the precision of the process and to conclude that such reports may be unreliable, since a single change in an allocation estimate may dramatically alter the resulting estimate of cost and/or profitability of a fund and may produce unintended consequences. The allocation information, including the Senior Officer's view that fund-by-fund estimations may be unreliable, was considered in the analysis by the Board.

The Board and the Senior Officer also reviewed information compiled by Federated comparing profitability information for Federated to other publicly held fund management companies. In this regard, the Senior Officer concluded that Federated's profit margins did not appear to be excessive. The Senior Officer also noted that Federated appeared financially sound, with the resources to fulfill its obligations under its contracts with the Funds.

The Senior Officer's Evaluation also discussed the notion of possible realization of “economies of scale” as a fund grows larger. The Board considered in this regard that the Adviser has made significant and long-term investments in areas that support all of the Federated family of funds, such as personnel and processes for the portfolio management, shareholder services, compliance, internal audit, and risk management functions; and systems technology; and that the benefits of these efforts (as well as any economies of scale, should they exist) were likely to be enjoyed by the fund family as a whole. Federated, as it does throughout the year, and again in connection with the Board's review, furnished information relative to revenue sharing or adviser paid fees. Federated and the Senior Officer noted that this information should be viewed to determine if there was an incentive to either not apply breakpoints or to apply breakpoints at higher levels and should not be viewed to determining the appropriateness of advisory fees, because it would represent marketing and distribution expenses. Finally, the Board also noted the absence of any applicable regulatory or industry guidelines on this subject, which (as discussed in the Senior Officer's Evaluation) is compounded by the lack of any common industry practice or general pattern with respect to structuring fund advisory fees with “breakpoints” that serve to reduce the fee as the fund attains a certain size.

The Senior Officer noted that, subject to the comments and recommendations made within his Evaluation, his observations and the information accompanying the Evaluation supported a finding by the Board that the management fees for each of the funds were reasonable. Under these circumstances, no objection was raised to the continuation of, the Fund's advisory contract.

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In its decision to continue an existing investment advisory contract, the Board was mindful of the potential disruptions of the Fund's operations and various risks, uncertainties and other effects that could occur as a result of a decision to terminate or not renew an advisory contract. In particular, the Board recognized that many shareholders have invested in the Fund on the strength of the Adviser's industry standing and reputation and with the expectation that the Adviser will have a continuing role in providing advisory services to the Fund. Thus, the Board's approval of the advisory contract reflected the fact that it is the shareholders who have effectively selected the Adviser by virtue of having invested in the Fund. The Board concluded that, in light of the factors discussed above, including the nature, quality and scope of the services provided to the Fund by the Adviser and its affiliates, continuation of the advisory contract was appropriate.

The Board based its decision to approve the advisory contract on the totality of the circumstances and relevant factors and with a view to past and future long-term considerations. Not all of the factors and considerations identified above were necessarily relevant to the Fund, nor did the Board consider any one of them to be determinative. With respect to the factors that were relevant, the Board's decision to approve the contract reflects its determination that Federated's performance and actions provided a satisfactory basis to support the decision to continue the existing arrangements.

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Voting Proxies on Fund Portfolio Securities

A description of the policies and procedures that the Fund uses to determine how to vote proxies, if any, relating to securities held in the Fund's portfolio is available, without charge and upon request, by calling 1-800-341-7400. A report on “Form N-PX” of how the Fund voted any such proxies during the most recent 12-month period ended June 30 is available via the Proxy Voting Record (Form N-PX) link associated with the Fund and share class name at www.FederatedInvestors.com/FundInformation. Form N-PX filings are also available at the SEC's website at www.sec.gov.

Quarterly Portfolio Schedule

The Fund files with the SEC a complete schedule of its portfolio holdings, as of the close of the first and third quarters of its fiscal year, on “Form N-Q.” These filings are available on the SEC's website at www.sec.gov and may be reviewed and copied at the SEC's Public Reference Room in Washington, DC. (Call 1-800-SEC-0330 for information on the operation of the Public Reference Room.) You may also access this information via the link to the Fund and share class name at www.FederatedInvestors.com/FundInformation.

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Mutual funds are not bank deposits or obligations, are not guaranteed by any bank and are not insured or guaranteed by the U.S. government, the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency. Investment in mutual funds involves investment risk, including the possible loss of principal. Although money market funds seek to maintain a stable net asset value of $1.00 per share, there is no assurance that they will be able to do so.

This Report is authorized for distribution to prospective investors only when preceded or accompanied by the Fund's Prospectus, which contains facts concerning its objective and policies, management fees, expenses and other information.

IMPORTANT NOTICE ABOUT FUND DOCUMENT DELIVERY    

In an effort to reduce costs and avoid duplicate mailings, the Fund(s) intend to deliver a single copy of certain documents to each household in which more than one shareholder of the Fund(s) resides (so-called “householding”), as permitted by applicable rules. The Fund's “householding” program covers its/their Prospectus and Statement of Additional Information, and supplements to each, as well as Semi-Annual and Annual Shareholder Reports and any Proxies or information statements. Shareholders must give their written consent to participate in the “householding” program. The Fund is also permitted to treat a shareholder as having given consent (“implied consent”) if (i) shareholders with the same last name, or believed to be members of the same family, reside at the same street address or receive mail at the same post office box, (ii) the Fund gives notice of its intent to “household” at least sixty (60) days before it begins “householding” and (iii) none of the shareholders in the household have notified the Fund(s) or their agent of the desire to “opt out” of “householding.” Shareholders who have granted written consent, or have been deemed to have granted implied consent, can revoke that consent and opt out of “householding” at any time: shareholders who purchased shares through an intermediary should contact their representative; other shareholders may call the Fund at 1-800-341-7400.

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Federated Government Cash Series

Federated Investors Funds
4000 Ericsson Drive
Warrendale, PA 15086-7561

Contact us at FederatedInvestors.com
or call 1-800-341-7400.

Federated Securities Corp., Distributor

CUSIP 147551204

0122604 (1/16)

Federated is a registered trademark of Federated Investors, Inc.
2016 ©Federated Investors, Inc.

Semi-Annual Shareholder Report

November 30, 2015

Ticker CMSXX

Federated Municipal Cash Series

A Portfolio of Cash Trust Series, Inc.

Not FDIC Insured
May Lose Value

No Bank Guarantee

CONTENTS

Portfolio of Investments Summary Tables	1
Portfolio of Investments	2
Financial Highlights	6
Statement of Assets and Liabilities	7
Statement of Operations	8
Statement of Changes in Net Assets	9
Notes to Financial Statements	10
Shareholder Expense Example	15
Evaluation and Approval of Advisory Contract	16
Voting Proxies on Fund Portfolio Securities	22
Quarterly Portfolio Schedule	22

Portfolio of Investments Summary Tables (unaudited)

At November 30, 2015, the Fund's portfolio composition¹ was as follows:

Portfolio Composition	Percentage of Total Net Assets
Variable Rate Demand Instruments	69.5%
Municipal Notes	5.3%
Other Assets and Liabilities—Net2	25.2%
TOTAL	100.0%

At November 30, 2015, the Fund's effective maturity schedule³ was as follows:

Securities With an Effective Maturity of:	Percentage of Total Net Assets
1-7 Days	69.5%
8-30 Days	0.0%
31-90 Days	5.3%
91-180 Days	0.0%
181 Days or more	0.0%
Other Assets and Liabilities—Net2	25.2%
TOTAL	100.0%

1	See the Fund's Prospectus and Statement of Additional Information for a description of these investments.
2	Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.
3	Effective maturity is determined in accordance with the requirements of Rule 2a-7 under the Investment Company Act of 1940, which regulates money market mutual funds.

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Portfolio of Investments

November 30, 2015 (unaudited)

Principal Amount or Shares		Value
	SHORT-TERM MUNICIPALS—74.8%1,2
	Alabama—0.2%
$185,000	Montgomery, AL IDB, (Series 2001) Weekly VRDNs (Hager Hinge)/(U.S. Bank, N.A. LOC), 0.110%, 12/3/2015	$185,000
	Arizona—0.5%
555,000	Casa Grande, AZ IDA, (Series 2002A) Weekly VRDNs (Price Cos., Inc.)/(Bank of America N.A. LOC), 0.170%, 12/3/2015	555,000
	Florida—4.5%
5,380,000	Collier County, FL IDA, (Series 2005) Weekly VRDNs (Ave Maria Utility Company)/(SunTrust Bank LOC), 0.220%, 12/2/2015	5,380,000
	Georgia—22.7%
850,000	Atlanta, GA, Urban Residential Finance Authority, (Series 1995) Weekly VRDNs (West End Housing Development)/(FNMA LOC), 0.150%, 12/3/2015	850,000
5,500,000	Atlanta, GA, Urban Residential Finance Authority, (Series 2006) Weekly VRDNs (Columbia at Sylvan Hills Apartments)/(FNMA LOC), 0.070%, 12/3/2015	5,500,000
2,625,000	Bartow County, GA Development Authority, (Series 2010) Weekly VRDNs (VMC Specialty Alloys LLC)/(Comerica Bank LOC), 0.010%, 12/3/2015	2,625,000
4,505,000	Columbia County, GA Development Authority, (Series 2002) Weekly VRDNs (Westwood Club Apartments)/(FNMA LOC), 0.020%, 12/3/2015	4,505,000
2,500,000	Fulton County, GA Development Authority, (Series 2008) Weekly VRDNs (Children's Healthcare of Atlanta, Inc.)/(Landesbank Hessen-Thuringen LIQ), 0.020%, 12/2/2015	2,500,000
5,000,000	Savannah, GA EDA, (Series 1995A) Weekly VRDNs (Home Depot, Inc.), 0.050%, 12/2/2015	5,000,000
6,000,000	Wayne County, GA, IDA, (Series 2000) Weekly VRDNs (Rayonier, Inc.)/(Bank of America N.A. LOC), 0.040%, 12/2/2015	6,000,000
	TOTAL	26,980,000
	Illinois—6.7%
825,000	Illinois Development Finance Authority IDB, (Series 1997) Weekly VRDNs (Tempco Electric Heater Corp.)/(JPMorgan Chase Bank, N.A. LOC), 0.460%, 12/3/2015	825,000
1,000,000	Illinois Development Finance Authority IDB, (Series 2001) Weekly VRDNs (Apogee Enterprises, Inc.)/(Comerica Bank LOC), 0.110%, 12/3/2015	1,000,000
3,835,000	Illinois Finance Authority—Solid Waste, (Series 2013) Weekly VRDNs (Kuusakoski US LLC)/(Fifth Third Bank, Cincinnati LOC), 0.120%, 12/3/2015	3,835,000

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Principal Amount or Shares		Value
	SHORT-TERM MUNICIPALS—continued1,2
	Illinois—continued
$2,300,000	Illinois Finance Authority, (Series 2008) Weekly VRDNs (Jasper Meats, Inc.)/(BMO Harris Bank, N.A. LOC), 0.140%, 12/3/2015	$2,300,000
	TOTAL	7,960,000
	Indiana—6.6%
5,500,000	Indianapolis, IN MFH, (Series 2007A: Forest Ridge Apartments) Weekly VRDNs (Pedcor Investments-2006-LXXXVIII LP)/(Citizens Bank, N.A., Providence LOC), 0.200%, 12/3/2015	5,500,000
2,400,000	Whiting, IN Environmental Facilities, Revenue Bonds (Series 2009), 5.00% Bonds (BP PLC), 1/4/2016	2,409,376
	TOTAL	7,909,376
	Kentucky—1.7%
2,070,000	Kentucky Housing Corp., (Series 2007) Weekly VRDNs (Arbors of Madisonville Apartments LP)/(U.S. Bank, N.A. LOC), 0.250%, 12/3/2015	2,070,000
	Louisiana—5.9%
2,000,000	Port of New Orleans, LA, (Series 2000) Weekly VRDNs (New Orleans Steamboat Co.)/(FHLB of Dallas LOC), 0.150%, 12/3/2015	2,000,000
5,000,000	St. James Parish, LA, (Series 2009) Weekly VRDNs (Louisiana Sugar Refining, LLC)/(Natixis LOC), 0.120%, 12/3/2015	5,000,000
	TOTAL	7,000,000
	Michigan—2.7%
1,450,000	Michigan State Finance Authority Revenue, Healthcare Equipment Program (Series C) Weekly VRDNs (Fifth Third Bank, Cincinnati LOC), 0.100%, 12/2/2015	1,450,000
1,750,000	Michigan State Hospital Finance Authority, (Series C) Weekly VRDNs (Fifth Third Bank, Cincinnati LOC), 0.100%, 12/2/2015	1,750,000
	TOTAL	3,200,000
	Missouri—2.0%
2,370,000	St. Louis County, MO IDA, (Series 2008A) Daily VRDNs (International Lutheran Laymen's League)/(Fifth Third Bank, Cincinnati LOC), 0.030%, 12/1/2015	2,370,000
	New York—1.1%
1,300,000	New York City, NY IDA, IDRBs (Series 2003) Weekly VRDNs (Novelty Crystal Corp.)/(TD Bank, N.A. LOC), 0.120%, 12/3/2015	1,300,000
	Ohio—7.1%
3,900,000	Avon, OH Water System, 1.00% BANs, 2/3/2016	3,904,423
4,500,000	Franklin County, OH Hospital Facility Authority, (Series 2008D) Weekly VRDNs (Nationwide Children's Hospital)/(Bank of New York Mellon LIQ), 0.010%, 12/3/2015	4,500,000

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3

Principal Amount or Shares		Value
	SHORT-TERM MUNICIPALS—continued1,2
	Ohio—continued
$100,000	Ohio State Air Quality Development Authority, (Series 2009C) Weekly VRDNs (Ohio Valley Electric Corp.)/(Bank of Tokyo-Mitsubishi UFJ Ltd. LOC), 0.010%, 12/3/2015	$100,000
	TOTAL	8,504,423
	South Carolina—2.5%
3,030,000	South Carolina Jobs-EDA, (Series 2007) Weekly VRDNs (ACI Industries LLC)/(Bank of America N.A. LOC), 0.200%, 12/3/2015	3,030,000
	Texas—3.4%
4,000,000	Port Arthur Navigation District, TX IDC, (Series 2006) Daily VRDNs (Air Products LP)/(GTD by Air Products & Chemicals, Inc.), 0.010%, 12/1/2015	4,000,000
	Virginia—5.5%
4,500,000	Harrisonburg, VA Redevelopment & Housing Authority, (Series 2008) Weekly VRDNs (Woodman West Preservation, LP)/(FNMA LOC), 0.020%, 12/3/2015	4,500,000
2,000,000	Loudoun County, VA IDA, (Series 2003E) Weekly VRDNs (Howard Hughes Medical Institute), 0.010%, 12/2/2015	2,000,000
	TOTAL	6,500,000
	Wisconsin—1.7%
2,000,000	Combined Locks, WI IDRB, (Series 1997) Weekly VRDNs (Appleton Papers)/(Fifth Third Bank, Cincinnati LOC), 0.160%, 12/3/2015	2,000,000
	TOTAL MUNICIPAL INVESTMENTS—74.8% (AT AMORTIZED COST)3	88,943,799
	OTHER ASSETS AND LIABILITIES - NET—25.2%4	30,016,778
	TOTAL NET ASSETS—100%	$118,960,577

Securities that are subject to the federal alternative minimum tax (AMT) represent 63.3% of the portfolio as calculated based upon total market value.

1 The Fund may only invest in securities rated in one of the two highest short-term rating categories by nationally recognized statistical rating organizations (NRSROs) or unrated securities of comparable quality. An NRSRO's two highest rating categories are determined without regard for sub-categories and gradations. For example, securities rated SP-1+, SP-1 or SP-2 by Standard & Poor's, MIG-1 or MIG-2 by Moody's Investors Service, or F-1+, F-1 or F-2 by Fitch Ratings, are all considered rated in one of the two highest short-term rating categories.

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Securities rated in the highest short-term rating category (and unrated securities of comparable quality) are identified as First Tier securities. Securities rated in the second highest short-term rating category (and unrated securities of comparable quality) are identified as Second Tier securities. The Fund follows applicable regulations in determining whether a security is rated and whether a security rated by multiple NRSROs in different rating categories should be identified as a First or Second Tier security.

At November 30, 2015, the portfolio securities were rated as follows:

Tier Rating Percentages Based on Total Market Value

First Tier	Second Tier
100.0%	0.0%

2	Current rate and next reset date shown for Variable Rate Demand Instruments.
3	Also represents cost for federal tax purposes.
4	Assets, other than investments in securities, less liabilities. A significant portion of this balance is the result of receivables for securities sold. See Statement of Assets and Liabilities.

Note: The categories of investments are shown as a percentage of total net assets at November 30, 2015.

Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below:

Level 1—quoted prices in active markets for identical securities.

Level 2—other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.). Also includes securities valued at amortized cost.

Level 3—significant unobservable inputs (including the Fund's own assumptions in determining the fair value of investments).

The inputs or methodology used for valuing securities are not an indication of the risk associated with investing in those securities.

As of November 30, 2015, all investments of the Fund are valued at amortized cost, which is considered a Level 2 input, in valuing the Fund's assets.

The following acronyms are used throughout this portfolio:

AMT	—Alternative Minimum Tax
BANs	—Bond Anticipation Notes
EDA	—Economic Development Authority
FHLB	—Federal Home Loan Bank
FNMA	—Federal National Mortgage Association
GTD	—Guaranteed
IDA	—Industrial Development Authority
IDB	—Industrial Development Bond
IDC	—Industrial Development Corporation
IDRB	—Industrial Development Revenue Bond
IDRBs	—Industrial Development Revenue Bonds
LIQ	—Liquidity Agreement
LLC	—Limited Liability Corporation
LOC	—Letter of Credit
LP	—Limited Partnership
MFH	—Multi-Family Housing
VRDNs	—Variable Rate Demand Notes

See Notes which are an integral part of the Financial Statements

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Financial Highlights

(For a Share Outstanding Throughout Each Period)

	Six Months Ended (unaudited) 11/30/2015	Year Ended May 31,
		2015	2014	2013	2012	2011
Net Asset Value, Beginning of Period	$1.00	$1.00	$1.00	$1.00	$1.00	$1.00
Income From Investment Operations:
Net investment income	—	—	—	—	—	—
Net realized gain on investments	0.0001	—	0.0001	0.0001	0.0001	0.0001
TOTAL FROM INVESTMENT OPERATIONS	0.0001	—	0.0001	0.0001	0.0001	0.0001
Less Distributions:
Distributions from net realized gain on investments	—	(0.000)1	(0.000)1	(0.000)1	(0.000)1	(0.000)1
Net Asset Value, End of Period	$1.00	$1.00	$1.00	$1.00	$1.00	$1.00
Total Return2	0.00%	0.00%3	0.02%	0.00%3	0.00%3	0.00%3
Ratios to Average Net Assets:
Net expenses	0.14%4	0.18%	0.23%	0.31%	0.42%	0.49%
Net investment income	0.00%4	0.00%	0.00%	0.00%	0.00%	0.00%
Expense waiver/reimbursement5	1.03%4	0.94%	0.89%	0.72%	0.68%	0.59%
Supplemental Data:
Net assets, end of period (000 omitted)	$118,961	$250,161	$317,849	$360,830	$461,541	$539,081

1	Represents less than $0.001.
2	Based on net asset value. Total returns for periods of less than one year are not annualized.
3	Represents less than 0.01%.
4	Computed on an annualized basis.
5	This expense decrease is reflected in both the net expense and the net investment income ratios shown above.

See Notes which are an integral part of the Financial Statements

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Statement of Assets and Liabilities

November 30, 2015 (unaudited)

Assets:
Total investment in securities, at amortized cost and fair value		$88,943,799
Cash		8,396,119
Income receivable		90,407
Receivable for investments sold		21,600,000
Receivable for shares sold		6,627
TOTAL ASSETS		119,036,952
Liabilities:
Payable for shares redeemed	$5,627
Payable to adviser (Note 4)	12,285
Payable for custodian fees	1,366
Payable for transfer agent fee	8,729
Payable for auditing fees	2,255
Payable for legal fees	4,352
Payable for portfolio accounting fees	21,827
Payable for share registration costs	12,019
Payable for insurance premiums	4,457
Accrued expenses (Note 4)	3,458
TOTAL LIABILITIES		76,375
Net assets for 118,894,019 shares outstanding		$118,960,577
Net Assets Consist of:
Paid-in capital		$118,887,026
Accumulated net realized gain on investments		73,551
TOTAL NET ASSETS		$118,960,577
Net Asset Value, Offering Price and Redemption Proceeds Per Share:
$118,960,577 ÷ 118,894,019 shares outstanding, no par value, unlimited shares authorized		$1.00

See Notes which are an integral part of the Financial Statements

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Statement of Operations

Six Months Ended November 30, 2015 (unaudited)

Investment Income:
Interest			$144,814
Expenses:
Investment adviser fee (Note 4)		$520,448
Administrative fee (Note 4)		81,492
Custodian fees		4,383
Transfer agent fee		109,738
Directors'/Trustees' fees (Note 4)		1,895
Auditing fees		26,855
Legal fees		11,569
Portfolio accounting fees		43,744
Distribution services fee (Note 4)		104,090
Other service fees (Note 2)		260,225
Share registration costs		20,025
Printing and postage		23,994
Miscellaneous (Note 4)		7,826
TOTAL EXPENSES		1,216,284
Waivers and Reimbursements:
Waiver of investment adviser fee (Note 4)	$(520,448)
Waivers/reimbursement of other operating expenses (Notes 2 and 4)	(551,022)
TOTAL WAIVERS AND REIMBURSEMENT		(1,071,470)
Net expenses			144,814
Net investment income			—
Net realized gain on investments			73,551
Change in net assets resulting from operations			$73,551

See Notes which are an integral part of the Financial Statements

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Statement of Changes in Net Assets

	Six Months Ended (unaudited) 11/30/2015	Year Ended 5/31/2015
Increase (Decrease) in Net Assets
Operations:
Net investment income	$—	$—
Net realized gain on investments	73,551	—
CHANGE IN NET ASSETS RESULTING FROM OPERATIONS	73,551	—
Distributions to Shareholders:
Distributions from net realized gain on investments	—	(4,693)
Share Transactions:
Proceeds from sale of shares	107,388,765	289,415,069
Net asset value of shares issued to shareholders in payment of distributions declared	—	4,677
Cost of shares redeemed	(238,662,847)	(357,102,871)
CHANGE IN NET ASSETS RESULTING FROM SHARE TRANSACTIONS	(131,274,082)	(67,683,125)
Change in net assets	(131,200,531)	(67,687,818)
Net Assets:
Beginning of period	250,161,108	317,848,926
End of period	$118,960,577	$250,161,108

See Notes which are an integral part of the Financial Statements

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Notes to Financial Statements

November 30, 2015 (unaudited)

1. ORGANIZATION

Cash Trust Series, Inc. (the “Corporation”) is registered under the Investment Company Act of 1940, as amended (the “Act”), as an open-end management investment company. The Corporation consists of four portfolios. The financial statements included herein are only those of Federated Municipal Cash Series (the “Fund”), a diversified portfolio. The financial statements of the other portfolios are presented separately. The assets of each portfolio are segregated and a shareholder's interest is limited to the portfolio in which shares are held. Each portfolio pays its own expenses. The investment objective of the Fund is to provide current income which is exempt from federal regular income tax consistent with stability of principal. Interest income from the Fund's investments may be subject to the federal AMT for individuals and corporations and state and local taxes.

2. SIGNIFICANT ACCOUNTING POLICIES

The following is a summary of significant accounting policies consistently followed by the Fund in the preparation of its financial statements. These policies are in conformity with U.S. generally accepted accounting principles (GAAP).

Investment Valuation

Securities are valued at amortized cost. Under the amortized cost valuation method, an investment is valued initially at its cost as determined in accordance with GAAP. The Fund then adjusts the amount of interest income accrued each day over the term of the investment to account for any difference between the initial cost of the investment and the amount payable at its maturity. If amortized cost is determined not to approximate fair value, the value of the portfolio securities will be determined in accordance with the procedures described below.

The Directors have ultimate responsibility for determining the fair value of investments. The Directors have appointed a valuation committee (“Valuation Committee”) comprised of officers of the Fund, Federated Investment Management Company (“Adviser”) and certain of the Adviser's affiliated companies to assist in determining fair value of securities and in overseeing the comparison of amortized cost to market-based value. The Directors have also authorized the use of pricing services recommended by the Valuation Committee to provide fair value evaluations of the current value of certain investments for purposes of monitoring the relationship of market-based value and amortized cost. The Valuation Committee employs various methods for reviewing third-party pricing-service evaluations including periodic reviews of third-party pricing services' policies, procedures and valuation methods (including key inputs and assumptions), and review of price challenges by the Adviser based on recent market activity. In the event that market quotations and price evaluations are not available for an investment, the Valuation Committee determines the fair value of the investment in accordance with procedures adopted by the Directors. The Directors periodically review and approve the fair valuations made by the Valuation Committee and any changes made to the procedures.

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Investment Income, Gains and Losses, Expenses and Distributions

Investment transactions are accounted for on a trade-date basis. Realized gains and losses from investment transactions are recorded on an identified-cost basis. Interest income and expenses are accrued daily. Distributions to shareholders are recorded on the ex-dividend date. Distributions of net investment income, if any, are declared daily and paid monthly.

For the six months ended November 30, 2015, unaffiliated third parties waived $101,564 of transfer agent fees.

Other Service Fees

The Fund may pay other service fees up to 0.25% of the average daily net assets of the Fund's Shares to unaffiliated financial intermediaries or to Federated Shareholder Services Company (FSSC) for providing services to shareholders and maintaining shareholder accounts. Subject to the terms described in the Expense Limitation note, FSSC may voluntarily reimburse the Fund for other service fees. For the six months ended November 30, 2015, unaffiliated third-party financial intermediaries waived the entire $260,225 of other service fees. This waiver can be modified or terminated at any time.

Premium and Discount Amortization

All premiums and discounts are amortized/accreted using the effective-interest-rate method.

Federal Taxes

It is the Fund's policy to comply with the Subchapter M provision of the Internal Revenue Code and to distribute to shareholders each year substantially all of its income. Accordingly, no provision for federal income tax is necessary. As of and during the six months ended November 30, 2015, the Fund did not have a liability for any uncertain tax positions. The Fund recognizes interest and penalties, if any, related to tax liabilities as income tax expense in the Statement of Operations. As of November 30, 2015, tax years 2012 through 2015 remain subject to examination by the Fund's major tax jurisdictions, which include the United States of America, the state of Maryland and the Commonwealth of Pennsylvania.

Other Taxes

As an open-end management investment company incorporated in the state of Maryland but domiciled in the Commonwealth of Pennsylvania, the Fund is subject to the Pennsylvania Franchise Tax. This franchise tax is assessed annually on the value of the Fund, as represented by average net assets for the tax year.

When-Issued and Delayed-Delivery Transactions

The Fund may engage in when-issued or delayed-delivery transactions. The Fund records when-issued securities on the trade date and maintains security positions such that sufficient liquid assets will be available to make payment for the securities purchased. Securities purchased on a when-issued or delayed-delivery basis are marked to market daily and begin earning interest on the settlement date. Losses may occur on these transactions due to changes in market conditions or the failure of counterparties to perform under the contract.

Restricted Securities

The Fund may purchase securities which are considered restricted. Restricted securities are securities that either: (a) cannot be offered for public sale without first being registered, or being able to take advantage of an exemption from registration, under the Securities Act of 1933; or (b) are subject to contractual restrictions on public sales. In some cases, when a security cannot be offered for public sale without first being registered, the issuer of the

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restricted security has agreed to register such securities for resale, at the issuer's expense, either upon demand by the Fund or in connection with another registered offering of the securities. Many such restricted securities may be resold in the secondary market in transactions exempt from registration. Restricted securities may be determined to be liquid under criteria established by the Directors. The Fund will not incur any registration costs upon such resales. Restricted securities are valued at amortized cost in accordance with Rule 2a-7 under the Act.

Other

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts of assets, liabilities, expenses and revenues reported in the financial statements. Actual results could differ from those estimated. The Fund applies Investment Company accounting and reporting guidance.

3. CAPITAL STOCK

The following table summarizes capital stock activity:

	Six Months Ended 11/30/2015	Year Ended 5/31/2015
Shares sold	107,388,765	289,415,069
Shares issued to shareholders in payment of distributions declared	—	4,677
Shares redeemed	(238,662,847)	(357,102,871)
NET CHANGE RESULTING FROM FUND SHARE TRANSACTIONS	(131,274,082)	(67,683,125)

4. INVESTMENT ADVISER FEE AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Adviser Fee

The advisory agreement between the Fund and the Adviser provides for an annual fee equal to 0.50% of the Fund's average daily net assets. Subject to the terms described in the Expense Limitation note, the Adviser may voluntarily choose to waive any portion of its fee. For the six months ended November 30, 2015, the Adviser voluntarily waived its entire fee of $520,448 and voluntarily reimbursed $85,143 of other operating expenses.

Administrative Fee

Federated Administrative Services (FAS), under the Administrative Services Agreement, provides the Fund with administrative personnel and services. For purposes of determining the appropriate rate breakpoint, “Investment Complex” is defined as all of the Federated Funds subject to a fee under the Administrative Services Agreement. The fee paid to FAS is based on the average daily net assets of the Investment Complex as specified below, plus certain out-of-pocket expenses:

Administrative Fee	Average Daily Net Assets of the Investment Complex
0.150%	on the first $5 billion
0.125%	on the next $5 billion
0.100%	on the next $10 billion
0.075%	on assets in excess of $20 billion

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Subject to the terms described in the Expense Limitation note, FAS may voluntarily choose to waive any portion of its fee. For the six months ended November 30, 2015, the annualized fee paid to FAS was 0.078% of average daily net assets of the Fund.

Distribution Services Fee

The Fund has adopted a Distribution Plan (the “Plan”) pursuant to Rule 12b-1 under the Act. Under the terms of the Plan, the Fund will reimburse Federated Securities Corp. (FSC), the principal distributor, from the daily net assets of the Fund to finance activities intended to result in the sale of these shares. The Plan provides that the Fund may incur distribution expenses of up to 0.35% of average daily net assets, annually, to reimburse FSC. Subject to the terms described in the Expense Limitation note, FSC may voluntarily choose to waive any portion of its fee. For the six months ended November 30, 2015, FSC voluntarily waived its entire fee of $104,090. When FSC receives fees, it may pay some or all of them to financial intermediaries whose customers purchase shares.

Expense Limitation

Due to the possibility of changes in market conditions and other factors, there can be no assurance that the level of waivers/reimbursement/reduction of Fund expenses reflected in the financial highlights will be maintained in the future. However, the Adviser and certain of its affiliates (which may include FSC, FAS and FSSC), on their own initiative, have agreed to waive certain amounts of their respective fees and/or reimburse expenses. Total annual fund operating expenses (as shown in the financial highlights, excluding extraordinary expenses and proxy-related expenses paid by the Fund, if any) paid by the Fund's Shares (after the voluntary waivers and/or reimbursements) will not exceed 1.05% (the “Fee Limit”), up to but not including the later of (the “Termination Date”): (a) August 1, 2016; or (b) the date of the Fund's next effective Prospectus. While the Adviser and its applicable affiliates currently do not anticipate terminating or increasing this arrangement prior to the Termination Date, this arrangement may only be terminated or the Fee Limit increased prior to the Termination Date with the agreement of the Directors.

Interfund Transactions

During the six months ended November 30, 2015, the Fund engaged in purchase and sale transactions with funds that have a common investment adviser (or affiliated investment advisers), common Directors/Trustees, and/or common Officers. These purchase and sale transactions complied with Rule 17a-7 under the Act and amounted to $300,965,000 and $364,120,000, respectively.

General

Certain Officers and Directors of the Fund are Officers and Directors or Trustees of certain of the above companies. To efficiently facilitate payment, Directors'/Trustees' fees and certain expenses related to conducting meetings of the Directors/Trustees and other miscellaneous expenses are paid by an affiliate of the Adviser which in due course are reimbursed by the Fund. Such expenses may be included in Accrued and Miscellaneous Expenses on the Statement of Assets and Liabilities and Statement of Operations, respectively.

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5. LINE OF CREDIT

The Fund participates in a $100,000,000 unsecured, uncommitted revolving line of credit (LOC) agreement with PNC Bank. The LOC was made available for extraordinary or emergency purposes, primarily for financing redemption payments. Borrowings are charged interest at a rate offered to the Fund by PNC Bank at the time of the borrowing. As of November 30, 2015, there were no outstanding loans. During the six months ended November 30, 2015, the Fund did not utilize the LOC.

6. INTERFUND LENDING

Pursuant to an Exemptive Order issued by the Securities and Exchange Commission (SEC), the Fund, along with other funds advised by subsidiaries of Federated Investors, Inc., may participate in an interfund lending program. This program provides an alternative credit facility allowing the Fund to borrow from other participating affiliated funds. As of November 30, 2015, there were no outstanding loans. During the six months ended November 30, 2015, the program was not utilized.

7. REGULATORY MATTERS

On July 23, 2014, the SEC voted to amend the rules under the Act which currently govern the operations of the Fund. A significant change resulting from these amendments will be a requirement that institutional prime funds (i.e. not retail as defined in the amendments), transact fund shares based on a market-based Net Asset Value (NAV). Other types of money market funds may continue to transact fund shares at an NAV calculated using the amortized cost valuation method. Among additional disclosure and other requirements, the amendments also will permit a money market fund, or, in certain circumstances, require a money market fund (other than a government money market fund which satisfies the requirements of the amended rules) to impose liquidity fees on redemptions, and permit a money market fund to limit (or gate) redemptions for up to 10 business days in any 90-day period. The amendments have staggered compliance dates. Compliance with a majority of these amendments will be required on October 14, 2016, two years after the effective date for the rule amendments. The degree to which a money market fund will be impacted by the rule amendments will depend upon the type of fund and type of investors (retail or institutional). At this time, management is evaluating the implications of these amendments and their impact to the Fund's operations, financial statements and accompanying notes.

8. SUBSEQUENT EVENTS

On December 11, 2015, Federated Municipal Obligations Fund acquired all or substantially all of the assets of the Fund in complete liquidation and termination of the Fund.

Management has evaluated subsequent events through the date the financial statements were issued and determined that no additional events occurred that require disclosure.

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Shareholder Expense Example (unaudited)

As a shareholder of the Fund, you incur ongoing costs, including management fees and to the extent applicable, distribution (12b-1) fees and/or other service fees and other Fund expenses. This Example is intended to help you to understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds. It is based on an investment of $1,000 invested at the beginning of the period and held for the entire period from June 1, 2015 to November 30, 2015.

ACTUAL EXPENSES

The first section of the table below provides information about actual account values and actual expenses. You may use the information in this section, together with the amount you invested, to estimate the expenses that you incurred over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number in the first section under the heading entitled “Expenses Paid During Period” to estimate the expenses attributable to your investment during this period.

HYPOTHETICAL EXAMPLE FOR COMPARISON PURPOSES

The second section of the table below provides information about hypothetical account values and hypothetical expenses based on the Fund's actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund's actual return. Thus, you should not use the hypothetical account values and expenses to estimate the actual ending account balance or your expenses for the period. Rather, these figures are required to be provided to enable you to compare the ongoing costs of investing in the Fund with other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

Please note that the expenses shown in the table are meant to highlight your ongoing costs only. Therefore, the second section of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds.

	Beginning Account Value 6/1/2015	Ending Account Value 11/30/2015	Expenses Paid During Period1,2
Actual	$1,000	$1,000.00	$0.70
Hypothetical (assuming a 5% return before expenses)	$1,000	$1,024.30	$0.71

1

Expenses are equal to the Fund's annualized net expense ratio of 0.14%, multiplied by the average account value over the period, multiplied by 183/366 (to reflect the one-half-year period).

2

Actual and Hypothetical expenses paid during the period utilizing the Fund's current Fee Limit of 1.05% (as reflected in the Notes to Financial Statements, Note 4 under Expense Limitation), multiplied by the average account value over the period, multiplied by 183/366 (to reflect expenses paid as if they had been in effect throughout the most recent one-half-year period) would be $5.25 and $5.30, respectively.

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Evaluation and Approval of Advisory Contract–May 2015

Federated Municipal Cash Series (the “Fund”)

Following a review and recommendation of approval by the Fund's independent directors, the Fund's Board reviewed and approved at its May 2015 meetings the Fund's investment advisory contract for an additional one-year term. The Board's decision regarding the contract reflects the exercise of its business judgment on whether to continue the existing arrangements.

In this connection, the Federated Funds' Board had previously appointed a Senior Officer, whose duties include specified responsibilities relating to the process by which advisory fees are to be charged to a Federated fund. The Senior Officer has the authority to retain consultants, experts, or staff as may be reasonably necessary to assist in the performance of his duties, reports directly to the Board, and may be terminated only with the approval of a majority of the independent members of the Board. The Senior Officer prepared and furnished to the Board an independent, written evaluation that covered topics discussed below (the “Evaluation”). The Board considered that Evaluation, along with other information, in deciding to approve the advisory contract.

The Board is also familiar with and considered judicial decisions concerning allegedly excessive investment advisory fees, which have indicated that the following factors may be relevant to an Adviser's fiduciary duty with respect to its receipt of compensation from a fund: the nature and quality of the services provided by the Adviser to a fund and its shareholders, including the performance and expenses of the fund and of comparable funds; the Adviser's cost of providing the services, including the profitability to the Adviser of providing advisory services to a fund; the extent to which the Adviser may realize “economies of scale” as a fund grows larger and, if such economies of scale exist, whether they have been shared with a fund and its shareholders or the family of funds; any “fall-out financial benefits” that accrue to the Adviser because of its relationship with a fund (including research services received from brokers that execute fund trades and any fees paid to affiliates of the Adviser for services rendered to a fund); comparative fee structures, including a comparison of fees paid to the Adviser with those paid by similar funds; and the extent of care, conscientiousness and independence with which the Board members perform their duties and their expertise, including whether they are fully informed about all facts the Board deems relevant to its consideration of the Adviser's services and fees. The Board noted that SEC disclosure requirements regarding the basis for the Board's approval of the Fund's advisory contract generally track the factors listed above. Consistent with these judicial decisions and SEC disclosure requirements, the Board also considered management fees

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charged to institutional and other clients of the Adviser for what might be viewed as like services. The Board was aware of these factors and was guided by them in its review of the Fund's advisory contract to the extent it considered them to be appropriate and relevant, as discussed further below.

The Board considered and weighed these circumstances in light of its substantial accumulated experience in governing the Fund and working with Federated on matters relating to the Federated funds, and was assisted in its deliberations by independent legal counsel. Throughout the year, and in connection with its May meetings, the Board requested and received substantial and detailed information about the Fund and the Federated organization that was in addition to the extensive materials that comprise and accompany the Senior Officer's Evaluation. Federated provided much of this information at each regular meeting of the Board, and furnished additional substantial information in connection with the May meeting at which the Board's formal review of the advisory contract occurred. At this May meeting, senior management of the Adviser also met with the independent directors and their counsel to discuss the materials presented and any other matters thought relevant by the Adviser or the directors. Between regularly scheduled meetings, the Board also received information on particular matters as the need arose. Thus, the Board's consideration of the advisory contract included review of the Senior Officer's Evaluation, accompanying data and additional information covering such matters as: the Adviser's investment philosophy, revenue, profitability, personnel and processes; investment and operating strategies; the Fund's short- and long-term performance (in absolute terms, both on a gross basis and net of expenses, as well as in relationship to its particular investment program and certain competitor or “peer group” funds and/or other benchmarks, as appropriate), and comments on the reasons for performance; the Fund's investment objectives; the Fund's expenses (including the advisory fee itself and the overall expense structure of the Fund, both in absolute terms and relative to similar and/or competing funds, with due regard for contractual or voluntary expense limitations); the use and allocation of brokerage commissions derived from trading the Fund's portfolio securities (if any); and the nature, quality and extent of the advisory and other services provided to the Fund by the Adviser and its affiliates. The Board also considered the preferences and expectations of Fund shareholders; the entrepreneurial risk assumed by the Adviser in sponsoring the funds; the continuing state of competition in the mutual fund industry and market practices; the range of comparable fees for similar funds in the mutual fund industry; the Fund's relationship to the Federated family of funds which include a comprehensive array of funds with different investment objectives, policies and strategies which are available for exchange without the incurrence of additional sales charges; compliance and audit reports concerning the Federated funds and the Federated companies that service them (including communications from regulatory agencies), as well as Federated's responses to any issues raised therein; and relevant developments in

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the mutual fund industry and how the Federated funds and/or Federated are responding to them. The Board's evaluation process is evolutionary. The criteria considered and the emphasis placed on relevant criteria change in recognition of changing circumstances in the mutual fund marketplace.

While mindful that courts have cautioned against giving such comparisons too much weight, the Board has found the use of comparisons of the Fund's fees and expenses to other mutual funds with comparable investment programs to be relevant. In this regard, the Board was presented with, and considered, information regarding the contractual advisory fee rates, net advisory fee rates and total expense ratios relative to a fund's peers. The Board focused on comparisons with other similar mutual funds more heavily than non-mutual fund products or services because it is believed that they are more relevant. For example, other mutual funds are the products most like the Fund, they are readily available to Fund shareholders as alternative investment vehicles, and they are the type of investment vehicle in fact chosen and maintained by the Fund's investors. The range of their fees and expenses therefore appears to be a relevant indicator of what consumers have found to be reasonable in the precise marketplace in which the Fund competes.

It was noted in the materials for the Board meeting that for the period covered by the Evaluation, the Fund's investment advisory fee was waived in its entirety. The Board reviewed the contractual advisory fee rate, net advisory fee rate and other expenses of the Fund with the Adviser and noted the position of the Fund's fee rates relative to its peers. In this regard, the Board noted that the contractual advisory fee rate was above the median of the relevant peer group, but the Board noted that the investment advisory fee was waived in its entirety and that the overall expense structure of the Fund remained competitive.

By contrast, the Senior Officer has reviewed Federated's fees for providing advisory services to products outside the Federated family of funds (e.g., institutional and separate accounts and sub-adviser services). He concluded that mutual funds and institutional accounts are inherently different products. Those differences include, but are not limited to, different types of targeted investors; being subject to different laws and regulations; different legal structures; different average account sizes and portfolio management techniques made necessary by different cash flows and different associated costs; and the time spent by portfolio managers and their teams, funds financial services, legal, compliance and risk management in reviewing securities pricing, addressing different administrative responsibilities, addressing different degrees of risk associated with management and a variety of different costs. The Senior Officer did not consider these fee schedules to be determinative in judging the appropriateness of mutual fund advisory fees.

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The Fund's ability to deliver competitive performance when compared to its peer group was also deemed to be relevant by the Board as a useful indicator of how the Adviser is executing the Fund's investment program, which in turn was one of the Board's considerations in reaching a conclusion that the nature, extent, and quality of the Adviser's investment management services were such as to warrant continuation of the advisory contract.

The Senior Officer reviewed information compiled by Federated, using data supplied by independent fund ranking organizations, regarding the performance of, and fees charged by, other mutual funds, noting his view that comparisons to fund peer groups may be helpful, though not conclusive, in judging the reasonableness of the proposed fees. The Board considered, in evaluating such comparisons, that in some cases individual funds may exhibit significant and unique differences in their objectives and management techniques when compared to other funds within an industry peer group.

The Fund's performance fell below the median of the relevant peer group for the one-year period covered by the Evaluation. The Board discussed the Fund's performance with the Adviser and recognized the efforts being undertaken by the Adviser. The Board will continue to monitor these efforts and the performance of the Fund in the context of the other factors considered relevant by the Board.

The Board also received financial information about Federated, including information regarding the compensation and benefits Federated derived from its relationships with the Federated funds. This information covered not only the fees under the advisory contracts, but also fees received by Federated's subsidiaries for providing other services to the Federated funds under separate contracts (e.g., for serving as the Federated funds' administrator). The information also detailed any indirect benefit Federated may derive from its receipt of research services from brokers who execute Federated fund trades. In addition, the Board considered the fact that, in order for a fund to be competitive in the marketplace, Federated and its affiliates frequently waived fees and/or reimbursed expenses and have disclosed to fund investors and/or indicated to the Board their intention to do so in the future, where appropriate. Moreover, the Board receives regular reporting as to the institution, adjustment or elimination of these voluntary waivers.

In addition, over the past two years, following discussions regarding the Senior Officer's recommendations, Federated made meaningful reductions to the contractual advisory fees for several Funds. In May 2014, the Senior Officer recommended that Federated review the fee structures of its money market funds to determine whether it would be appropriate to consider alternative pricing structures. Federated has combined that review with its consideration of the re-structuring of its money market fund product line in response to the recently adopted amendments to Rule 2a-7 under the Investment Company Act of 1940, as amended (the “1940 Act”).

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At the Board meeting in May 2015, following previous recommendations of the Senior Officer, Federated proposed, and the Board approved, reductions in the contractual advisory fees of certain other Funds.

Federated furnished information, requested by the Senior Officer, that reported revenues on a fund-by-fund basis and made estimates of the allocation of expenses on a fund-by-fund basis, using allocation methodologies specified by the Senior Officer. The Senior Officer noted that, while these cost allocation reports apply consistent allocation processes, the inherent difficulties in allocating costs continues to cause the Senior Officer to question the precision of the process and to conclude that such reports may be unreliable, since a single change in an allocation estimate may dramatically alter the resulting estimate of cost and/or profitability of a fund and may produce unintended consequences. The allocation information, including the Senior Officer's view that fund-by-fund estimations may be unreliable, was considered in the analysis by the Board.

The Board and the Senior Officer also reviewed information compiled by Federated comparing profitability information for Federated to other publicly held fund management companies. In this regard, the Senior Officer concluded that Federated's profit margins did not appear to be excessive. The Senior Officer also noted that Federated appeared financially sound, with the resources to fulfill its obligations under its contracts with the Funds.

The Senior Officer's Evaluation also discussed the notion of possible realization of “economies of scale” as a fund grows larger. The Board considered in this regard that the Adviser has made significant and long-term investments in areas that support all of the Federated family of funds, such as personnel and processes for the portfolio management, shareholder services, compliance, internal audit, and risk management functions; and systems technology; and that the benefits of these efforts (as well as any economies of scale, should they exist) were likely to be enjoyed by the fund family as a whole. Federated, as it does throughout the year, and again in connection with the Board's review, furnished information relative to revenue sharing or adviser paid fees. Federated and the Senior Officer noted that this information should be viewed to determine if there was an incentive to either not apply breakpoints or to apply breakpoints at higher levels and should not be viewed to determining the appropriateness of advisory fees, because it would represent marketing and distribution expenses. Finally, the Board also noted the absence of any applicable regulatory or industry guidelines on this subject, which (as discussed in the Senior Officer's Evaluation) is compounded by the lack of any common industry practice or general pattern with respect to structuring fund advisory fees with “breakpoints” that serve to reduce the fee as the fund attains a certain size.

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The Senior Officer noted that, subject to the comments and recommendations made within his Evaluation, his observations and the information accompanying the Evaluation supported a finding by the Board that the management fees for each of the funds were reasonable. Under these circumstances, no objection was raised to the continuation of, the Fund's advisory contract.

In its decision to continue an existing investment advisory contract, the Board was mindful of the potential disruptions of the Fund's operations and various risks, uncertainties and other effects that could occur as a result of a decision to terminate or not renew an advisory contract. In particular, the Board recognized that many shareholders have invested in the Fund on the strength of the Adviser's industry standing and reputation and with the expectation that the Adviser will have a continuing role in providing advisory services to the Fund. Thus, the Board's approval of the advisory contract reflected the fact that it is the shareholders who have effectively selected the Adviser by virtue of having invested in the Fund. The Board concluded that, in light of the factors discussed above, including the nature, quality and scope of the services provided to the Fund by the Adviser and its affiliates, continuation of the advisory contract was appropriate.

The Board based its decision to approve the advisory contract on the totality of the circumstances and relevant factors and with a view to past and future long-term considerations. Not all of the factors and considerations identified above were necessarily relevant to the Fund, nor did the Board consider any one of them to be determinative. With respect to the factors that were relevant, the Board's decision to approve the contract reflects its determination that Federated's performance and actions provided a satisfactory basis to support the decision to continue the existing arrangements.

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Voting Proxies on Fund Portfolio Securities

A description of the policies and procedures that the Fund uses to determine how to vote proxies, if any, relating to securities held in the Fund's portfolio is available, without charge and upon request, by calling 1-800-341-7400. A report on “Form N-PX” of how the Fund voted any such proxies during the most recent 12-month period ended June 30 is available via the Proxy Voting Record (Form N-PX) link associated with the Fund and share class name at www.FederatedInvestors.com/FundInformation. Form N-PX filings are also available at the SEC's website at www.sec.gov.

Quarterly Portfolio Schedule

The Fund files with the SEC a complete schedule of its portfolio holdings, as of the close of the first and third quarters of its fiscal year, on “Form N-Q.” These filings are available on the SEC's website at www.sec.gov and may be reviewed and copied at the SEC's Public Reference Room in Washington, DC. (Call 1-800-SEC-0330 for information on the operation of the Public Reference Room.) You may also access this information via the link to the Fund and share class name at www.FederatedInvestors.com/FundInformation.

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Mutual funds are not bank deposits or obligations, are not guaranteed by any bank and are not insured or guaranteed by the U.S. government, the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency. Investment in mutual funds involves investment risk, including the possible loss of principal. Although money market funds seek to maintain a stable net asset value of $1.00 per share, there is no assurance that they will be able to do so.

This Report is authorized for distribution to prospective investors only when preceded or accompanied by the Fund's Prospectus, which contains facts concerning its objective and policies, management fees, expenses and other information.

IMPORTANT NOTICE ABOUT FUND DOCUMENT DELIVERY    

In an effort to reduce costs and avoid duplicate mailings, the Fund(s) intend to deliver a single copy of certain documents to each household in which more than one shareholder of the Fund(s) resides (so-called “householding”), as permitted by applicable rules. The Fund's “householding” program covers its/their Prospectus and Statement of Additional Information, and supplements to each, as well as Semi-Annual and Annual Shareholder Reports and any Proxies or information statements. Shareholders must give their written consent to participate in the “householding” program. The Fund is also permitted to treat a shareholder as having given consent (“implied consent”) if (i) shareholders with the same last name, or believed to be members of the same family, reside at the same street address or receive mail at the same post office box, (ii) the Fund gives notice of its intent to “household” at least sixty (60) days before it begins “householding” and (iii) none of the shareholders in the household have notified the Fund(s) or their agent of the desire to “opt out” of “householding.” Shareholders who have granted written consent, or have been deemed to have granted implied consent, can revoke that consent and opt out of “householding” at any time: shareholders who purchased shares through an intermediary should contact their representative; other shareholders may call the Fund at 1-800-341-7400.

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Federated Municipal Cash Series

Federated Investors Funds
4000 Ericsson Drive
Warrendale, PA 15086-7561

Contact us at FederatedInvestors.com
or call 1-800-341-7400.

Federated Securities Corp., Distributor

CUSIP 147551303

0122605 (1/16)

Federated is a registered trademark of Federated Investors, Inc.
2016 ©Federated Investors, Inc.

Semi-Annual Shareholder Report

November 30, 2015

Ticker CTPXX

Federated Prime Cash Series

A Portfolio of Cash Trust Series, Inc.

Not FDIC Insured
May Lose Value

No Bank Guarantee

CONTENTS

Portfolio of Investments Summary Tables	1
Portfolio of Investments	2
Financial Highlights	6
Statement of Assets and Liabilities	7
Statement of Operations	8
Statement of Changes in Net Assets	9
Notes to Financial Statements	10
Shareholder Expense Example	16
Evaluation and Approval of Advisory Contract	18
Voting Proxies on Fund Portfolio Securities	24
Quarterly Portfolio Schedule	24

Portfolio of Investments Summary Tables (unaudited)

At November 30, 2015, the Fund's portfolio composition¹ was as follows:

Security Type	Percentage of Total Net Assets
Commercial Paper and Notes	23.2%
Variable Rate Instruments	19.2%
Bank Instruments	12.1%
Repurchase Agreements	45.5%
Other Assets and Liabilities—Net2,3	0.0%
TOTAL	100.0%

At Novermber 30, 2015, the Fund's effective maturity schedule⁴ was as follows:

Securities With an Effective Maturity of:	Percentage of Total Net Assets
1-7 Days	65.2%
8-30 Days	16.5%
31-90 Days	16.0%
91-180 Days	2.1%
181 Days or more	0.2%
Other Assets and Liabilities—Net2,3	0.0%
TOTAL	100.0%

1	See the Fund's Prospectus and Statement of Additional Information for more complete information regarding these security types. With respect to this table, Commercial Paper and Notes includes commercial paper and corporate bonds with interest rates that are fixed or that reset periodically.
2	Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.
3	Represents less than 0.1%.
4	Effective maturity is determined in accordance with the requirements of Rule 2a-7 under the Investment Company Act of 1940, which regulates money market mutual funds.

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Portfolio of Investments

November 30, 2015 (unaudited)

Principal Amount			Value
		CERTIFICATES OF DEPOSIT—12.1%
		Finance - Banking—12.1%
$70,000,000		ABN Amro Bank NV, 0.380%, 1/5/2016	$69,974,165
69,000,000		Bank of Tokyo-Mitsubishi UFJ Ltd., 0.380%—0.390%, 1/19/2016 - 2/8/2016	69,000,000
50,000,000		Credit Agricole Corporate and Investment Bank, 0.380%, 12/1/2015	50,000,000
15,000,000		DNB Bank ASA, 0.100%, 12/4/2015	15,000,000
15,000,000		DZ Bank AG Deutsche Zentral-Genossenschaftsbank, 0.390%, 2/2/2016	15,000,000
50,000,000		Standard Chartered Bank PLC, 0.350%, 12/4/2015	50,000,000
10,000,000		Sumitomo Mitsui Banking Corp., 0.400%, 1/14/2016	10,000,000
5,000,000		Toronto Dominion Bank, 0.750%, 8/8/2016	5,000,000
		TOTAL CERTIFICATES OF DEPOSIT	283,974,165
		COMMERCIAL PAPER—22.0%1
		Finance - Banking—20.1%
80,000,000	2,3	BNP Paribas SA, 0.130%—0.360%, 12/1/2015 - 12/2/2015	79,999,819
25,000,000	2,3	Commonwealth Bank of Australia, 0.353%, 12/1/2015	25,000,000
25,000,000	2,3	Commonwealth Bank of Australia, 0.370%, 12/4/2015	25,000,000
25,000,000		HSBC USA, Inc., 0.406%, 12/7/2015	24,998,313
20,000,000	2,3	J.P. Morgan Securities LLC, 0.481%, 12/28/2015	20,000,000
25,000,000	2,3	J.P. Morgan Securities LLC, 0.603%, 4/1/2016	24,949,167
30,000,000	2,3	LMA-Americas LLC, 0.320%, 1/6/2016	29,990,400
35,000,000	2,3	Manhattan Asset Funding Company LLC, 0.360%, 12/14/2015	34,995,450
55,000,000		NRW.Bank, 0.135%, 12/3/2015	54,999,587
25,000,000	2,3	National Australia Bank Ltd., Melbourne, 0.346%, 12/14/2015	25,000,000
114,000,000	2,3	Nationwide Building Society, 0.400%, 12/3/2015 - 1/4/2016	113,972,333
10,000,000		Standard Chartered Bank PLC, 0.370%, 12/28/2015	9,997,225
		TOTAL	468,902,294
		Finance - Retail—1.9%
45,000,000	2,3	Chariot Funding LLC, 0.401%—0.501%, 1/28/2016 - 2/22/2016	44,963,378
		TOTAL COMMERCIAL PAPER	513,865,672
		CORPORATE BONDS—1.2%
		Finance - Commercial—0.2%
4,540,000		General Electric Capital Corp., 5.000%, 1/8/2016	4,561,118
		Finance - Securities—1.0%
23,369,000	2,3	GE Capital International Funding Co., 0.964%, 4/15/2016	23,369,333
		TOTAL CORPORATE BONDS	27,930,451

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Principal Amount			Value
		NOTES - VARIABLE—19.2%4
		Aerospace/Auto—4.3%
$18,000,000		BMW US Capital LLC, (GTD by Bayerische Motoren Werke AG), 0.447%, 1/6/2016	$18,000,000
15,000,000		BMW US Capital LLC, (GTD by Bayerische Motoren Werke AG), 0.454%, 2/5/2016	15,000,000
42,000,000		Toyota Motor Credit Corp., (Toyota Motor Corp. SA), 0.297%, 12/15/2015	42,000,000
25,000,000		Toyota Motor Credit Corp., (Toyota Motor Corp. SA), 0.523%, 1/7/2016	25,000,000
		TOTAL	100,000,000
		Finance - Banking—14.0%
25,000,000		Bank of Montreal, 0.306%, 12/11/2015	25,000,000
14,000,000		Bank of Montreal, 0.349%, 12/18/2015	14,000,000
10,000,000		Bank of Montreal, 0.373%, 12/23/2015	10,000,000
25,000,000		Bank of Nova Scotia, Toronto, 0.439%, 12/2/2015	25,000,000
5,000,000	2,3	Bedford Row Funding Corp., (GTD by Royal Bank of Canada, Montreal), 0.386%, 3/16/2016	5,000,000
24,000,000		HSBC Bank USA, N.A., 0.355%, 12/8/2015	24,000,000
11,935,000		RBS Insurance Trust, Series 2015, (BOKF, N.A. LOC), 0.170%, 12/3/2015	11,935,000
25,000,000		Rabobank Nederland NV, Utrecht, 0.383%, 12/31/2015	25,000,000
25,000,000		Rabobank Nederland NV, Utrecht, 0.399%, 3/18/2016	25,000,000
25,000,000		Royal Bank of Canada, Montreal, 0.315%, 12/8/2015	25,000,000
30,000,000		Royal Bank of Canada, Montreal, 0.409%, 1/11/2016	30,000,000
20,000,000		Royal Bank of Canada, Montreal, 0.484%, 1/4/2016	20,000,000
2,500,000		Sun Valley, Inc., (Wells Fargo Bank, N.A. LOC), 0.240%, 12/4/2015	2,500,000
26,000,000		Toronto Dominion Bank, 0.343%, 12/7/2015	26,000,000
25,000,000		Toronto Dominion Bank, 0.363%, 12/22/2015	25,000,000
25,000,000		Toronto Dominion Bank, 0.430%, 12/4/2015	25,000,000
7,800,000		Village Green Finance Co. LLC, (Series 1997), (Wells Fargo Bank, N.A. LOC), 0.190%, 12/2/2015	7,800,000
		TOTAL	326,235,000
		Finance—Commercial—0.5%
11,730,000	2,3	Mountain Creek Properties LLC, (General Electric Capital Corp. LOC), 0.200%, 12/3/2015	11,730,000
		Government Agency—0.4%
9,920,000		Capital Trust Agency, FL, (FNMA LOC), 0.140%, 12/3/2015	9,920,000
		TOTAL NOTES - VARIABLE	447,885,000

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Principal Amount		Value
	REPURCHASE AGREEMENTS—45.5%
$392,458,000	Interest in $1,850,000,000 joint repurchase agreement 0.13%, dated 11/30/2015 under which Mitsubishi UFJ Securities (USA), Inc. will repurchase securities provided as collateral for $1,850,006,681 on 12/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency securities with various maturities to 12/20/2064 and the market value of those underlying securities was $1,904,584,922.	$392,458,000
170,000,000	Interest in $500,000,000 joint repurchase agreement 0.13%, dated 11/30/2015 under which Mizuho Securities USA, Inc. will repurchase securities provided as collateral for $500,001,806 on 12/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency securities with various maturities to 12/25/2049 and the market value of those underlying securities was $512,215,106.	170,000,000
500,000,000	Interest in $2,500,000,000 joint repurchase agreement 0.13%, dated 11/30/2015 under which Natixis Financial Products LLC will repurchase securities provided as collateral for $2,500,009,028 on 12/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Government Agency and U.S. Treasury securities with various maturities to 9/15/2057 and the market value of those underlying securities was $2,564,470,823.	500,000,000
	TOTAL REPURCHASE AGREEMENTS	1,062,458,000
	TOTAL INVESTMENTS—100.0% (AT AMORTIZED COST)5	2,336,113,288
	OTHER ASSETS AND LIABILITIES - NET—0.0%6	13,465
	TOTAL NET ASSETS—100%	$2,336,126,753

1	Discount rate at time of purchase.
2	Denotes a restricted security that either: (a) cannot be offered for public sale without first being registered, or being able to take advantage of an exemption from registration, under the Securities Act of 1933; or (b) is subject to a contractual restriction on public sales. At November 30, 2015, these restricted securities amounted to $463,969,880, which represented 19.9% of total net assets.
3	Denotes a restricted security that may be resold without restriction to “qualified institutional buyers” as defined in Rule 144A under the Securities Act of 1933 and that the Fund has determined to be liquid under criteria established by the Fund's Board of Trustees (the “Trustees”). At November 30, 2015, these liquid restricted securities amounted to $463,969,880, which represented 19.9% of total net assets.
4	Denotes a variable rate security with current rate and next reset date shown.
5	Also represents cost for federal tax purposes.
6	Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.

Note: The categories of investments are shown as a percentage of total net assets at November 30, 2015.

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4

Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below:

Level 1—quoted prices in active markets for identical securities.

Level 2—other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.). Also includes securities valued at amortized cost.

Level 3—significant unobservable inputs (including the Fund's own assumptions in determining the fair value of investments).

The inputs or methodology used for valuing securities are not an indication of the risk associated with investing in those securities.

As of November 30, 2015, all investments of the Fund are valued at amortized cost, which is considered a Level 2 input, in valuing the Fund's assets.

The following acronyms are used throughout this portfolio:

FNMA	—Federal National Mortgage Association
GTD	—Guaranteed
LOC	—Letter of Credit

See Notes which are an integral part of the Financial Statements

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Financial Highlights

(For a Share Outstanding Throughout Each Period)

	Six Months Ended (unaudited) 11/30/2015	Year Ended May 31,
		2015	2014	2013	2012	2011
Net Asset Value, Beginning of Period	$1.00	$1.00	$1.00	$1.00	$1.00	$1.00
Income From Investment Operations:
Net investment income	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001
Net realized and unrealized gain (loss) on investments	0.0001	0.0001	0.0001	0.0001	(0.000)1	0.0001
TOTAL FROM INVESTMENT OPERATIONS	0.0001	0.0001	0.0001	0.0001	0.0001	0.0001
Less Distributions:
Distributions from net investment income	(0.000)1	(0.000)1	(0.000)1	(0.000)1	(0.000)1	(0.000)1
Distributions from net realized gain on investments	(0.000)1	(0.000)1	(0.000)1	(0.000)1	(0.000)1	(0.000)1
TOTAL DISTRIBUTIONS	(0.000)1	(0.000)1	(0.000)1	(0.000)1	(0.000)1	(0.000)1
Net Asset Value, End of Period	$1.00	$1.00	$1.00	$1.00	$1.00	$1.00
Total Return2	0.01%	0.01%	0.01%	0.01%	0.01%	0.01%
Ratios to Average Net Assets:
Net expenses	0.33%3	0.27%	0.27%	0.35%	0.38%	0.43%
Net investment income	0.01%3	0.01%	0.01%	0.01%	0.01%	0.01%
Expense waiver/reimbursement4	0.77%3	0.80%	0.82%	0.73%	0.70%	0.65%
Supplemental Data:
Net assets, end of period (000 omitted)	$2,336,127	$2,860,851	$2,926,756	$2,955,903	$2,966,768	$4,559,876

1	Represents less than $0.001.
2	Based on net asset value. Total returns for periods of less than one year are not annualized.
3	Computed on an annualized basis.
4	This expense decrease is reflected in both the net expense and the net investment income ratios shown above.

See Notes which are an integral part of the Financial Statements

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Statement of Assets and Liabilities

November 30, 2015 (unaudited)

Assets:
Investment in repurchase agreements	$1,062,458,000
Investment in securities	1,273,655,288
Total investment in securities, at amortized cost and fair value		$2,336,113,288
Cash		41,373
Income receivable		485,010
Receivable for shares sold		97,854
Receivable from adviser		11,707
TOTAL ASSETS		2,336,749,232
Liabilities:
Payable for shares redeemed	14,210
Payable for custodian fees	19,185
Payable for transfer agent fee	320,735
Payable for Directors'/Trustees' fees (Note 4)	353
Payable for portfolio accounting fees	44,997
Payable for share registration costs	22,073
Payable for printing and postage	171,534
Accrued expenses (Note 4)	29,392
TOTAL LIABILITIES		622,479
Net assets for 2,336,103,122 shares outstanding		$2,336,126,753
Net Assets Consist of:
Paid-in capital		$2,336,103,122
Accumulated net realized gain on investments		23,667
Distributions in excess of net investment income		(36)
TOTAL NET ASSETS		$2,336,126,753
Net Asset Value, Offering Price and Redemption Proceeds Per Share:
$2,336,126,753 ÷ 2,336,103,122 shares outstanding, $0.001 par value, 12,500,000,000 shares authorized		$1.00

See Notes which are an integral part of the Financial Statements

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Statement of Operations

Six Months Ended November 30, 2015 (unaudited)

Investment Income:
Interest			$4,798,102
Expenses:
Investment adviser fee (Note 4)		$7,054,364
Administrative fee (Note 4)		1,104,518
Custodian fees		71,803
Transfer agent fee		1,566,869
Directors'/Trustees' fees (Note 4)		13,237
Auditing fees		24,156
Legal fees		6,353
Portfolio accounting fees		99,982
Distribution services fee (Note 4)		1,410,873
Other service fees (Notes 2 and 4)		3,527,182
Share registration costs		188,906
Printing and postage		429,296
Taxes		30,745
Miscellaneous (Note 4)		19,122
TOTAL EXPENSES		15,547,406
Waivers:
Waiver of investment adviser fee (Note 4)	$(5,951,735)
Waivers of other operating expenses (Notes 2 and 4)	(4,938,055)
TOTAL WAIVERS, REIMBURSEMENTS AND REDUCTION		(10,889,790)
Net expenses			4,657,616
Net investment income			140,486
Net realized gain on investments			147,294
Change in net assets resulting from operations			$287,780

See Notes which are an integral part of the Financial Statements

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Statement of Changes in Net Assets

	Six Months Ended (unaudited) 11/30/2015	Year Ended 5/31/2015
Increase (Decrease) in Net Assets
Operations:
Net investment income	$140,486	$296,253
Net realized gain on investments	147,294	10,695
CHANGE IN NET ASSETS RESULTING FROM OPERATIONS	287,780	306,948
Distributions to Shareholders:
Distributions from net investment income	(140,603)	(296,183)
Distributions from net realized gain on investments	(134,200)	(8,673)
CHANGE IN NET ASSETS RESULTING FROM DISTRIBUTIONS TO SHAREHOLDERS	(274,803)	(304,856)
Share Transactions:
Proceeds from sale of shares	1,591,293,046	2,992,899,413
Net asset value of shares issued to shareholders in payment of distributions declared	271,531	303,734
Cost of shares redeemed	(2,116,301,538)	(3,059,110,597)
CHANGE IN NET ASSETS RESULTING FROM SHARE TRANSACTIONS	(524,736,961)	(65,907,450)
Change in net assets	(526,723,984)	(65,905,358)
Net Assets:
Beginning of period	2,860,850,737	2,926,756,095
End of period (including undistributed (distributions in excess of) net investment income of $(36) and $81, respectively)	$2,336,126,753	$2,860,850,737

See Notes which are an integral part of the Financial Statements

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Notes to Financial Statements

November 30, 2015 (unaudited)

1. ORGANIZATION

Cash Trust Series, Inc. (the “Corporation”) is registered under the Investment Company Act of 1940, as amended (the “Act”), as a diversified open-end management investment company. The Corporation consists of four portfolios. The financial statements included herein are only those of Federated Prime Cash Series (the “Fund”), a diversified portfolio. The financial statements of the other portfolios are presented separately. The assets of each portfolio are segregated and a shareholder's interest is limited to the portfolio in which shares are held. Each portfolio pays its own expenses. The investment objective of the Fund is current income consistent with stability of principal and liquidity.

2. SIGNIFICANT ACCOUNTING POLICIES

The following is a summary of significant accounting policies consistently followed by the Fund in the preparation of its financial statements. These policies are in conformity with U.S. generally accepted accounting principles (GAAP).

Investment Valuation

Securities are valued at amortized cost. Under the amortized cost valuation method, an investment is valued initially at its cost as determined in accordance with GAAP. The Fund then adjusts the amount of interest income accrued each day over the term of the investment to account for any difference between the initial cost of the investment and the amount payable at its maturity. If amortized cost is determined not to approximate fair value, the value of the portfolio securities will be determined in accordance with the procedures described below.

The Directors have ultimate responsibility for determining the fair value of investments. The Directors have appointed a valuation committee (“Valuation Committee”) comprised of officers of the Fund, Federated Investment Management Company (“Adviser”) and certain of the Adviser's affiliated companies to assist in determining fair value of securities and in overseeing the comparison of amortized cost to market-based value. The Directors have also authorized the use of pricing services recommended by the Valuation Committee to provide fair value evaluations of the current value of certain investments for purposes of monitoring the relationship of market-based value and amortized cost. The Valuation Committee employs various methods for reviewing third-party pricing-service evaluations including periodic reviews of third-party pricing services' policies, procedures and valuation methods (including key inputs and assumptions), and review of price challenges by the Adviser based on recent market activity. In the event that market quotations and price evaluations are not available for an investment, the Valuation Committee determines the fair value of the investment in accordance with procedures adopted by the Directors. The Directors periodically review and approve the fair valuations made by the Valuation Committee and any changes made to the procedures.

Repurchase Agreements

The Fund may invest in repurchase agreements for short-term liquidity purposes. It is the policy of the Fund to require the other party to a repurchase agreement to transfer to the Fund's custodian or sub-custodian eligible securities or cash with a market value (after transaction costs) at least equal to the repurchase price to be paid under the repurchase

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agreement. The eligible securities are transferred to accounts with the custodian or sub-custodian in which the Fund holds a “securities entitlement” and exercises “control” as those terms are defined in the Uniform Commercial Code. The Fund has established procedures for monitoring the market value of the transferred securities and requiring the transfer of additional eligible securities if necessary to equal at least the repurchase price. These procedures also allow the other party to require securities to be transferred from the account to the extent that their market value exceeds the repurchase price or in exchange for other eligible securities of equivalent market value.

The insolvency of the other party or other failure to repurchase the securities may delay the disposition of the underlying securities or cause the Fund to receive less than the full repurchase price. Under the terms of the repurchase agreement, any amounts received by the Fund in excess of the repurchase price and related transaction costs must be remitted to the other party.

The Fund may enter into repurchase agreements in which eligible securities are transferred into joint trading accounts maintained by the custodian or sub-custodian for investment companies and other clients advised by the Fund's Adviser and its affiliates. The Fund will participate on a pro rata basis with the other investment companies and clients in its share of the securities transferred under such repurchase agreements and in its share of proceeds from any repurchase or other disposition of such securities.

Repurchase agreements are subject to Master Netting Agreements which are agreements between the Fund and its counterparties that provide for the net settlement of all transactions and collateral with the Fund, through a single payment, in the event of default or termination. Amounts presented on the Portfolio of Investments and Statement of Assets and Liabilities are not net settlement amounts but gross. As indicated above, the cash or securities to be repurchased, as shown on the Portfolio of Investments, exceeds the repurchase price to be paid under the agreement reducing the net settlement amount to zero.

Investment Income, Gains and Losses, Expenses and Distributions

Investment transactions are accounted for on a trade-date basis. Realized gains and losses from investment transactions are recorded on an identified-cost basis. Interest income and expenses are accrued daily. Distributions to shareholders are recorded on the ex-dividend date. Distributions of net investment income are declared daily and paid monthly.

Other Service Fees

The Fund may pay other service fees up to 0.25% of the average daily net assets of the Fund's Shares to unaffiliated financial intermediaries or to Federated Shareholder Services Company (FSSC) for providing services to shareholders and maintaining shareholder accounts. Subject to the terms described in the Expense Limitation note, FSSC may voluntarily reimburse the Fund for other service fees. In addition, for the six months ended November 30, 2015, unaffiliated third-party financial intermediaries waived $3,527,182 of other service fees. This wavier can be modified or terminated at any time.

Premium and Discount Amortization

All premiums and discounts are amortized/accreted using the effective-interest-rate method.

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Federal Taxes

It is the Fund's policy to comply with the Subchapter M provision of the Internal Revenue Code and to distribute to shareholders each year substantially all of its income. Accordingly, no provision for federal income tax is necessary. As of and during the six months ended November 30, 2015, the Fund did not have a liability for any uncertain tax positions. The Fund recognizes interest and penalties, if any, related to tax liabilities as income tax expense in the Statement of Operations. As of November 30, 2015, tax years 2012 through 2015 remain subject to examination by the Fund's major tax jurisdictions, which include the United States of America, the state of Maryland and the Commonwealth of Pennsylvania.

Other Taxes

As an open-end management investment company incorporated in the state of Maryland but domiciled in the Commonwealth of Pennsylvania, the Fund is subject to the Pennsylvania Franchise Tax. This franchise tax is assessed annually on the value of the Fund, as represented by average net assets for the tax year.

When-Issued and Delayed-Delivery Transactions

The Fund may engage in when-issued or delayed-delivery transactions. The Fund records when-issued securities on the trade date and maintains security positions such that sufficient liquid assets will be available to make payment for the securities purchased. Securities purchased on a when-issued or delayed-delivery basis are marked to market daily and begin earning interest on the settlement date. Losses may occur on these transactions due to changes in market conditions or the failure of counterparties to perform under the contract.

Restricted Securities

The Fund may purchase securities which are considered restricted. Restricted securities are securities that either: (a) cannot be offered for public sale without first being registered, or being able to take advantage of an exemption from registration, under the Securities Act of 1933; or (b) are subject to contractual restrictions on public sales. In some cases, when a security cannot be offered for public sale without first being registered, the issuer of the restricted security has agreed to register such securities for resale, at the issuer's expense, either upon demand by the Fund or in connection with another registered offering of the securities. Many such restricted securities may be resold in the secondary market in transactions exempt from registration. Restricted securities may be determined to be liquid under criteria established by the Directors. The Fund will not incur any registration costs upon such resales. Restricted securities are valued at amortized cost in accordance with Rule 2a-7 under the Act.

Other

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts of assets, liabilities, expenses and revenues reported in the financial statements. Actual results could differ from those estimated. The Fund applies Investment Company accounting and reporting guidance.

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3. CAPITAL STOCK

The following table summarizes capital stock activity:

	Six Months Ended 11/30/2015	Year Ended 5/31/2015
Shares sold	1,591,293,046	2,992,899,413
Shares issued to shareholders in payment of distributions declared	271,531	303,734
Shares redeemed	(2,116,301,538)	(3,059,110,597)
NET CHANGE RESULTING FROM FUND SHARE TRANSACTIONS	(524,736,961)	(65,907,450)

4. INVESTMENT ADVISER FEE AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Adviser Fee

The advisory agreement between the Fund and the Adviser provides for an annual fee equal to 0.50% of the Fund's average daily net assets. Subject to the terms described in the Expense Limitation note, the Adviser may voluntarily choose to waive any portion of its fee. For the six months ended November 30, 2015, the Adviser voluntarily waived $5,951,735 of its fee.

Administrative Fee

Federated Administrative Services (FAS), under the Administrative Services Agreement, provides the Fund with administrative personnel and services. For purposes of determining the appropriate rate breakpoint, “Investment Complex” is defined as all of the Federated Funds subject to a fee under the Administrative Services Agreement. The fee paid to FAS is based on the average daily net assets of the Investment Complex as specified below, plus certain out-of-pocket expenses:

Administrative Fee	Average Daily Net Assets of the Investment Complex
0.150%	on the first $5 billion
0.125%	on the next $5 billion
0.100%	on the next $10 billion
0.075%	on assets in excess of $20 billion

Subject to the terms described in the Expense Limitation note, FAS may voluntarily choose to waive any portion of its fee. For the six months ended November 30, 2015, the annualized fee paid to FAS was 0.078% of average daily net assets of the Fund.

Distribution Services Fee

The Fund has adopted a Distribution Plan (the “Plan”) pursuant to Rule 12b-1 under the Act. Under the terms of the Plan, the Fund will reimburse Federated Securities Corp. (FSC), the principal distributor, from the daily net assets of the Fund to finance activities intended to result in the sale of these shares. The Plan provides that the Fund may incur distribution expenses of up to 0.35% of average daily net assets, annually, to reimburse FSC. Subject to the terms described in the Expense Limitation note, FSC may voluntarily choose to waive any portion of its fee. For the six months ended November 30, 2015, FSC voluntarily waived its entire fee of $1,410,873. When FSC receives fees, it may pay some or all of them to financial intermediaries whose customers purchase shares.

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Expense Limitation

Due to the possibility of changes in market conditions and other factors, there can be no assurance that the level of waivers/reimbursement/reduction of Fund expenses reflected in the financial highlights will be maintained in the future. However, the Adviser and certain of its affiliates (which may include FSC, FAS and FSSC) on their own initiative have agreed to waive certain amounts of their respective fees and/or reimburse expenses. Total annual fund operating expenses (as shown in the financial highlights, excluding extraordinary expenses and proxy-related expenses paid by the Fund, if any) paid by the Fund (after the voluntary waivers and/or reimbursements) will not exceed 1.05% (the “Fee Limit”), up to but not including the later of (the “Termination Date”): (a) August 1, 2016; or (b) the date of the Fund's next effective Prospectus. While the Adviser and its applicable affiliates currently do not anticipate terminating or increasing these arrangements prior to the Termination Date, these arrangements may only be terminated or the Fee Limit increased prior to the Termination Date with the agreement of the Directors.

Interfund Transactions

During the six months ended November 30, 2015, the Fund engaged in sale transactions with funds that have a common investment adviser (or affiliated investment advisers), common Directors/Trustees and/or common Officers. These sale transactions compiled with Rule 17a-7 under the Act and amounted to $68,875,000.

General

Certain Officers and Directors of the Fund are Officers and Directors or Trustees of certain of the above companies. To efficiently facilitate payment, Directors'/Trustees' fees and certain expenses related to conducting meetings of the Directors/Trustees and other miscellaneous expenses are paid by an affiliate of the Adviser which in due course are reimbursed by the Fund. Such expenses may be included in Accrued and Miscellaneous Expenses on the Statement of Assets and Liabilities and Statement of Operations, respectively.

5. CONCENTRATION OF RISK

A substantial part of the Fund's portfolio may be comprised of obligations of banks. As a result, the Fund may be more susceptible to any economic, business, political or other developments which generally affect these entities.

6. LINE OF CREDIT

The Fund participates in a $100,000,000 unsecured, uncommitted revolving line of credit (LOC) agreement with PNC Bank. The LOC was made available for extraordinary or emergency purposes, primarily for financing redemption payments. Borrowings are charged interest at a rate offered to the Fund by PNC Bank at the time of the borrowing. As of November 30, 2015, there were no outstanding loans. During the six months ended November 30, 2015, the Fund did not utilize the LOC.

7. INTERFUND LENDING

Pursuant to an Exemptive Order issued by the Securities and Exchange Commission (SEC), the Fund, along with other funds advised by subsidiaries of Federated Investors, Inc., may participate in an interfund lending program. This program provides an alternative credit facility allowing the Fund to borrow from other participating affiliated funds. As of November 30, 2015, there were no outstanding loans. During the six months ended November 30, 2015, the program was not utilized.

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8. regulatory matters

On July 23, 2014, the SEC voted to amend the rules under the Act which currently govern the operations of the Fund. A significant change resulting from these amendments will be a requirement that institutional prime funds (i.e., not retail as defined in the amendments), transact fund shares based on a market-based Net Asset Value (NAV). Other types of money market funds may continue to transact fund shares at an NAV calculated using the amortized cost valuation method. Among additional disclosure and other requirements, the amendments also will permit a money market fund, or, in certain circumstances, require a money market fund (other than a government money market fund which satisfies the requirements of the amendments) to impose liquidity fees on redemptions, and permit a money market fund to limit (or gate) redemptions for up to 10 business days in any 90-day period. The amendments have staggered compliance dates. Compliance with a majority of these amendments will be required on October 14, 2016, two years after the effective date for the rule amendments. The degree to which a money market fund will be impacted by the rule amendments will depend upon the type of fund and type of investors (retail or institutional). At this time, management is evaluating the implications of these amendments and their impact to the Fund's operations, financial statements and accompanying notes.

9. SUBSEQUENT EVENTS

On December 11, 2015, Federated Prime Cash Obligations Fund acquired all or substantially all of the assets of the Fund in complete liquidation and termination of the Fund.

Management has evaluated subsequent events through the date the financial statements were issued and determined that no additional events occurred that require disclosure.

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Shareholder Expense Example (unaudited)

As a shareholder of the Fund, you incur ongoing costs, including management fees and to the extent applicable, distribution (12b-1) fees and/or other service fees and other Fund expenses. This Example is intended to help you to understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds. It is based on an investment of $1,000 invested at the beginning of the period and held for the entire period from June 1, 2015 to November 30, 2015.

ACTUAL EXPENSES

The first section of the table below provides information about actual account values and actual expenses. You may use the information in this section, together with the amount you invested, to estimate the expenses that you incurred over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number in the first section under the heading entitled “Expenses Paid During Period” to estimate the expenses attributable to your investment during this period.

HYPOTHETICAL EXAMPLE FOR COMPARISON PURPOSES

The second section of the table below provides information about hypothetical account values and hypothetical expenses based on the Fund's actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund's actual return. Thus, you should not use the hypothetical account values and expenses to estimate the actual ending account balance or your expenses for the period. Rather, these figures are required to be provided to enable you to compare the ongoing costs of investing in the Fund with other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

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Please note that the expenses shown in the table are meant to highlight your ongoing costs only. Therefore, the second section of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds.

	Beginning Account Value 6/1/2015	Ending Account Value 11/30/2015	Expenses Paid During Period1,2
Actual	$1,000	$1,000.10	$1.65
Hypothetical (assuming a 5% return before expenses)	$1,000	$1,023.35	$1.67

1

Expenses are equal to the Fund's annualized net expense ratio of 0.33%, multiplied by the average account value over the period, multiplied by 183/366 (to reflect the one-half-year period).

2

Actual and Hypothetical expenses paid during the period utilizing the Fund's current Fee Limit of 1.05% (as reflected in the Notes to Financial Statements, Note 4 under Expense Limitation), multiplied by the average account value over the period, multiplied by 183/366 (to reflect expenses paid as if they had been in effect throughout the most recent one-half-year period) would be $5.25 and $5.30, respectively.

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Evaluation and Approval of Advisory Contract–May 2015

Federated Prime Cash Series (the “Fund”)

Following a review and recommendation of approval by the Fund's independent directors, the Fund's Board reviewed and approved at its May 2015 meetings the Fund's investment advisory contract for an additional one-year term. The Board's decision regarding the contract reflects the exercise of its business judgment on whether to continue the existing arrangements.

In this connection, the Federated Funds' Board had previously appointed a Senior Officer, whose duties include specified responsibilities relating to the process by which advisory fees are to be charged to a Federated fund. The Senior Officer has the authority to retain consultants, experts, or staff as may be reasonably necessary to assist in the performance of his duties, reports directly to the Board, and may be terminated only with the approval of a majority of the independent members of the Board. The Senior Officer prepared and furnished to the Board an independent, written evaluation that covered topics discussed below (the “Evaluation”). The Board considered that Evaluation, along with other information, in deciding to approve the advisory contract.

The Board is also familiar with and considered judicial decisions concerning allegedly excessive investment advisory fees, which have indicated that the following factors may be relevant to an Adviser's fiduciary duty with respect to its receipt of compensation from a fund: the nature and quality of the services provided by the Adviser to a fund and its shareholders, including the performance and expenses of the fund and of comparable funds; the Adviser's cost of providing the services, including the profitability to the Adviser of providing advisory services to a fund; the extent to which the Adviser may realize “economies of scale” as a fund grows larger and, if such economies of scale exist, whether they have been shared with a fund and its shareholders or the family of funds; any “fall-out financial benefits” that accrue to the Adviser because of its relationship with a fund (including research services received from brokers that execute fund trades and any fees paid to affiliates of the Adviser for services rendered to a fund); comparative fee structures, including a comparison of fees paid to the Adviser with those paid by similar funds; and the extent of care, conscientiousness and independence with which the Board members perform their duties and their expertise, including whether they are fully informed about all facts the Board deems relevant to its consideration of the Adviser's services and fees. The Board noted that SEC disclosure requirements regarding the basis for the Board's approval of the Fund's advisory contract generally track the factors listed above. Consistent with these judicial decisions and SEC disclosure requirements, the Board also considered management fees

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charged to institutional and other clients of the Adviser for what might be viewed as like services. The Board was aware of these factors and was guided by them in its review of the Fund's advisory contract to the extent it considered them to be appropriate and relevant, as discussed further below.

The Board considered and weighed these circumstances in light of its substantial accumulated experience in governing the Fund and working with Federated on matters relating to the Federated funds, and was assisted in its deliberations by independent legal counsel. Throughout the year, and in connection with its May meetings, the Board requested and received substantial and detailed information about the Fund and the Federated organization that was in addition to the extensive materials that comprise and accompany the Senior Officer's Evaluation. Federated provided much of this information at each regular meeting of the Board, and furnished additional substantial information in connection with the May meeting at which the Board's formal review of the advisory contract occurred. At this May meeting, senior management of the Adviser also met with the independent directors and their counsel to discuss the materials presented and any other matters thought relevant by the Adviser or the directors. Between regularly scheduled meetings, the Board also received information on particular matters as the need arose. Thus, the Board's consideration of the advisory contract included review of the Senior Officer's Evaluation, accompanying data and additional information covering such matters as: the Adviser's investment philosophy, revenue, profitability, personnel and processes; investment and operating strategies; the Fund's short- and long-term performance (in absolute terms, both on a gross basis and net of expenses, as well as in relationship to its particular investment program and certain competitor or “peer group” funds and/or other benchmarks, as appropriate), and comments on the reasons for performance; the Fund's investment objectives; the Fund's expenses (including the advisory fee itself and the overall expense structure of the Fund, both in absolute terms and relative to similar and/or competing funds, with due regard for contractual or voluntary expense limitations); the use and allocation of brokerage commissions derived from trading the Fund's portfolio securities (if any); and the nature, quality and extent of the advisory and other services provided to the Fund by the Adviser and its affiliates. The Board also considered the preferences and expectations of Fund shareholders; the entrepreneurial risk assumed by the Adviser in sponsoring the funds; the continuing state of competition in the mutual fund industry and market practices; the range of comparable fees for similar funds in the mutual fund industry; the Fund's relationship to the Federated family of funds which include a comprehensive array of funds with different investment objectives, policies and strategies which are available for exchange without the incurrence of additional sales charges; compliance and audit reports concerning the Federated funds and the Federated companies that service them (including communications from regulatory agencies), as well as Federated's responses to any issues raised therein; and relevant developments in

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the mutual fund industry and how the Federated funds and/or Federated are responding to them. The Board's evaluation process is evolutionary. The criteria considered and the emphasis placed on relevant criteria change in recognition of changing circumstances in the mutual fund marketplace.

While mindful that courts have cautioned against giving such comparisons too much weight, the Board has found the use of comparisons of the Fund's fees and expenses to other mutual funds with comparable investment programs to be relevant. In this regard, the Board was presented with, and considered, information regarding the contractual advisory fee rates, net advisory fee rates and total expense ratios relative to a fund's peers. The Board focused on comparisons with other similar mutual funds more heavily than non-mutual fund products or services because it is believed that they are more relevant. For example, other mutual funds are the products most like the Fund, they are readily available to Fund shareholders as alternative investment vehicles, and they are the type of investment vehicle in fact chosen and maintained by the Fund's investors. The range of their fees and expenses therefore appears to be a relevant indicator of what consumers have found to be reasonable in the precise marketplace in which the Fund competes.

The Board reviewed the contractual advisory fee rate, net advisory fee rate where partially waived and other expenses of the Fund and noted the position of the Fund's fee rates relative to its peers. In this regard, the Board noted that the contractual advisory fee rate was above the median of the relevant peer group, but the Board noted the applicable waivers and reimbursements and that the overall expense structure of the Fund remained competitive. The Board will continue to monitor advisory fees and other expenses borne by the Fund in the context of the other factors considered relevant by the Board.

By contrast, the Senior Officer has reviewed Federated's fees for providing advisory services to products outside the Federated family of funds (e.g., institutional and separate accounts and sub-adviser services). He concluded that mutual funds and institutional accounts are inherently different products. Those differences include, but are not limited to, different types of targeted investors; being subject to different laws and regulations; different legal structures; different average account sizes and portfolio management techniques made necessary by different cash flows and different associated costs; and the time spent by portfolio managers and their teams, funds financial services, legal, compliance and risk management in reviewing securities pricing, addressing different administrative responsibilities, addressing different degrees of risk associated with management and a variety of different costs. The Senior Officer did not consider these fee schedules to be determinative in judging the appropriateness of mutual fund advisory fees.

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The Fund's ability to deliver competitive performance when compared to its peer group was also deemed to be relevant by the Board as a useful indicator of how the Adviser is executing the Fund's investment program, which in turn was one of the Board's considerations in reaching a conclusion that the nature, extent, and quality of the Adviser's investment management services were such as to warrant continuation of the advisory contract.

The Senior Officer reviewed information compiled by Federated, using data supplied by independent fund ranking organizations, regarding the performance of, and fees charged by, other mutual funds, noting his view that comparisons to fund peer groups may be helpful, though not conclusive, in judging the reasonableness of the proposed fees. The Board considered, in evaluating such comparisons, that in some cases individual funds may exhibit significant and unique differences in their objectives and management techniques when compared to other funds within an industry peer group.

The Fund's performance was above the median of the relevant peer group for the one-year period covered by the Evaluation.

The Board also received financial information about Federated, including information regarding the compensation and benefits Federated derived from its relationships with the Federated funds. This information covered not only the fees under the advisory contracts, but also fees received by Federated's subsidiaries for providing other services to the Federated funds under separate contracts (e.g., for serving as the Federated funds' administrator). The information also detailed any indirect benefit Federated may derive from its receipt of research services from brokers who execute Federated fund trades. In addition, the Board considered the fact that, in order for a fund to be competitive in the marketplace, Federated and its affiliates frequently waived fees and/or reimbursed expenses and have disclosed to fund investors and/or indicated to the Board their intention to do so in the future, where appropriate. Moreover, the Board receives regular reporting as to the institution, adjustment or elimination of these voluntary waivers.

In addition, over the past two years, following discussions regarding the Senior Officer's recommendations, Federated made meaningful reductions to the contractual advisory fees for several Funds. In May 2014, the Senior Officer recommended that Federated review the fee structures of its money market funds to determine whether it would be appropriate to consider alternative pricing structures. Federated has combined that review with its consideration of the re-structuring of its money market fund product line in response to the recently adopted amendments to Rule 2a-7 under the Investment Company Act of 1940, as amended (the “1940 Act”).

At the Board meeting in May 2015, following previous recommendations of the Senior Officer, Federated proposed, and the Board approved, reductions in the contractual advisory fees of certain other Funds.

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Federated furnished information, requested by the Senior Officer, that reported revenues on a fund-by-fund basis and made estimates of the allocation of expenses on a fund-by-fund basis, using allocation methodologies specified by the Senior Officer. The Senior Officer noted that, while these cost allocation reports apply consistent allocation processes, the inherent difficulties in allocating costs continues to cause the Senior Officer to question the precision of the process and to conclude that such reports may be unreliable, since a single change in an allocation estimate may dramatically alter the resulting estimate of cost and/or profitability of a fund and may produce unintended consequences. The allocation information, including the Senior Officer's view that fund-by-fund estimations may be unreliable, was considered in the analysis by the Board.

The Board and the Senior Officer also reviewed information compiled by Federated comparing profitability information for Federated to other publicly held fund management companies. In this regard, the Senior Officer concluded that Federated's profit margins did not appear to be excessive. The Senior Officer also noted that Federated appeared financially sound, with the resources to fulfill its obligations under its contracts with the Funds.

The Senior Officer's Evaluation also discussed the notion of possible realization of “economies of scale” as a fund grows larger. The Board considered in this regard that the Adviser has made significant and long-term investments in areas that support all of the Federated family of funds, such as personnel and processes for the portfolio management, shareholder services, compliance, internal audit, and risk management functions; and systems technology; and that the benefits of these efforts (as well as any economies of scale, should they exist) were likely to be enjoyed by the fund family as a whole. Federated, as it does throughout the year, and again in connection with the Board's review, furnished information relative to revenue sharing or adviser paid fees. Federated and the Senior Officer noted that this information should be viewed to determine if there was an incentive to either not apply breakpoints or to apply breakpoints at higher levels and should not be viewed to determining the appropriateness of advisory fees, because it would represent marketing and distribution expenses. Finally, the Board also noted the absence of any applicable regulatory or industry guidelines on this subject, which (as discussed in the Senior Officer's Evaluation) is compounded by the lack of any common industry practice or general pattern with respect to structuring fund advisory fees with “breakpoints” that serve to reduce the fee as the fund attains a certain size.

The Senior Officer noted that, subject to the comments and recommendations made within his Evaluation, his observations and the information accompanying the Evaluation supported a finding by the Board that the management fees for each of the funds were reasonable. Under these circumstances, no objection was raised to the continuation of, the Fund's advisory contract.

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In its decision to continue an existing investment advisory contract, the Board was mindful of the potential disruptions of the Fund's operations and various risks, uncertainties and other effects that could occur as a result of a decision to terminate or not renew an advisory contract. In particular, the Board recognized that many shareholders have invested in the Fund on the strength of the Adviser's industry standing and reputation and with the expectation that the Adviser will have a continuing role in providing advisory services to the Fund. Thus, the Board's approval of the advisory contract reflected the fact that it is the shareholders who have effectively selected the Adviser by virtue of having invested in the Fund. The Board concluded that, in light of the factors discussed above, including the nature, quality and scope of the services provided to the Fund by the Adviser and its affiliates, continuation of the advisory contract was appropriate.

The Board based its decision to approve the advisory contract on the totality of the circumstances and relevant factors and with a view to past and future long-term considerations. Not all of the factors and considerations identified above were necessarily relevant to the Fund, nor did the Board consider any one of them to be determinative. With respect to the factors that were relevant, the Board's decision to approve the contract reflects its determination that Federated's performance and actions provided a satisfactory basis to support the decision to continue the existing arrangements.

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Voting Proxies on Fund Portfolio Securities

A description of the policies and procedures that the Fund uses to determine how to vote proxies, if any, relating to securities held in the Fund's portfolio is available, without charge and upon request, by calling 1-800-341-7400. A report on “Form N-PX” of how the Fund voted any such proxies during the most recent 12-month period ended June 30 is available via the Proxy Voting Record (Form N-PX) link associated with the Fund and share class name at www.FederatedInvestors.com/FundInformation. Form N-PX filings are also available at the SEC's website at www.sec.gov.

Quarterly Portfolio Schedule

The Fund files with the SEC a complete schedule of its portfolio holdings, as of the close of the first and third quarters of its fiscal year, on “Form N-Q.” These filings are available on the SEC's website at www.sec.gov and may be reviewed and copied at the SEC's Public Reference Room in Washington, DC. (Call 1-800-SEC-0330 for information on the operation of the Public Reference Room.) You may also access this information via the link to the Fund and share class name at www.FederatedInvestors.com/FundInformation.

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Mutual funds are not bank deposits or obligations, are not guaranteed by any bank and are not insured or guaranteed by the U.S. government, the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency. Investment in mutual funds involves investment risk, including the possible loss of principal. Although money market funds seek to maintain a stable net asset value of $1.00 per share, there is no assurance that they will be able to do so.

This Report is authorized for distribution to prospective investors only when preceded or accompanied by the Fund's Prospectus, which contains facts concerning its objective and policies, management fees, expenses and other information.

IMPORTANT NOTICE ABOUT FUND DOCUMENT DELIVERY    

In an effort to reduce costs and avoid duplicate mailings, the Fund(s) intend to deliver a single copy of certain documents to each household in which more than one shareholder of the Fund(s) resides (so-called “householding”), as permitted by applicable rules. The Fund's “householding” program covers its/their Prospectus and Statement of Additional Information, and supplements to each, as well as Semi-Annual and Annual Shareholder Reports and any Proxies or information statements. Shareholders must give their written consent to participate in the “householding” program. The Fund is also permitted to treat a shareholder as having given consent (“implied consent”) if (i) shareholders with the same last name, or believed to be members of the same family, reside at the same street address or receive mail at the same post office box, (ii) the Fund gives notice of its intent to “household” at least sixty (60) days before it begins “householding” and (iii) none of the shareholders in the household have notified the Fund(s) or their agent of the desire to “opt out” of “householding.” Shareholders who have granted written consent, or have been deemed to have granted implied consent, can revoke that consent and opt out of “householding” at any time: shareholders who purchased shares through an intermediary should contact their representative; other shareholders may call the Fund at 1-800-341-7400.

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Federated Prime Cash Series

Federated Investors Funds
4000 Ericsson Drive
Warrendale, PA 15086-7561

Contact us at FederatedInvestors.com
or call 1-800-341-7400.

Federated Securities Corp., Distributor

CUSIP 147551105

0122606 (1/16)

Federated is a registered trademark of Federated Investors, Inc.
2016 ©Federated Investors, Inc.

Semi-Annual Shareholder Report

November 30, 2015

Ticker CTTXX

Federated Treasury Cash Series

A Portfolio of Cash Trust Series, Inc.

Not FDIC Insured
May Lose Value

No Bank Guarantee

CONTENTS

Portfolio of Investments Summary Tables	1
Portfolio of Investments	2
Financial Highlights	5
Statement of Assets and Liabilities	6
Statement of Operations	7
Statement of Changes in Net Assets	8
Notes to Financial Statements	9
Shareholder Expense Example	15
Evaluation and Approval of Advisory Contract	17
Voting Proxies on Fund Portfolio Securities	23
Quarterly Portfolio Schedule	23

Portfolio of Investments Summary Tables (unaudited)

At November 30, 2015, the Fund's portfolio composition¹ was as follows:

Portfolio Composition	Percentage of Total Net Assets
Repurchase Agreements	76.4%
U.S. Treasury Securities	23.6%
Other Assets and Liabilities—Net2,3	0.0%
TOTAL	100.0%

At November 30, 2015, the Fund's effective maturity⁴ schedule was as follows:

Securities With an Effective Maturity of:	Percentage of Total Net Assets
1-7 Days	87.3%
8-30 Days	0.0%
31-90 Days	8.9%
91-180 Days	3.4%
181 Days or more	0.4%
Other Assets and Liabilities—Net2,3	0.0%
TOTAL	100.0%

1	See the Fund's Prospectus and Statement of Additional Information for a description of the principal types of securities in which the Fund invests.
2	Represents less than 0.1%.
3	Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.
4	Effective maturity is determined in accordance with the requirements of Rule 2a-7 under the Investment Company Act of 1940, which regulates money market mutual funds.

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Portfolio of Investments

November 30, 2015 (unaudited)

Principal Amount			Value
		U.S. TREASURIES—23.6%
$50,000,000	1	United States Treasury Bills, 0.055%, 12/3/2015	$49,999,847
50,000,000	1	United States Treasury Bills, 0.080%, 1/14/2016	49,995,111
4,000,000	1	United States Treasury Bills, 0.175%, 4/28/2016	3,997,103
45,000,000	2	United States Treasury Floating Rate Notes, 0.187%—0.211%, 12/1/2015	44,999,879
5,000,000		United States Treasury Notes, 0.250%, 4/15/2016	4,997,634
2,000,000		United States Treasury Notes, 0.375%, 1/31/2016	2,000,649
14,000,000		United States Treasury Notes, 0.375%, 3/15/2016	14,003,639
1,000,000		United States Treasury Notes, 1.500%, 6/30/2016	1,006,379
2,500,000		United States Treasury Notes, 1.750%, 5/31/2016	2,517,869
7,000,000		United States Treasury Notes, 2.000%, 4/30/2016	7,046,587
25,250,000		United States Treasury Notes, 2.125%, 12/31/2015	25,288,996
		TOTAL U.S. TREASURIES	205,853,693
		REPURCHASE AGREEMENTS—76.4%
150,000,000		Interest in $200,000,000 joint repurchase agreement 0.12%, dated 11/30/2015 under which Bank of Nova Scotia will repurchase securities provided as collateral for $200,000,667 on 12/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 2/15/2045 and the market value of those underlying securities was $204,000,734.	150,000,000
100,000,000		Interest in $1,750,000,000 joint repurchase agreement 0.11%, dated 11/30/2015 under which BNP Paribas Securities Corp. will repurchase securities provided as collateral for $1,750,005,347 on 12/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 5/15/2045 and the market value of those underlying securities was $1,785,005,505.	100,000,000
90,000,000		Interest in $100,000,000 joint repurchase agreement 0.10%, dated 11/30/2015 under which CIBC World Markets Corp. will repurchase securities provided as collateral for $100,000,278 on 12/1/2015. The securities provided as collateral at the end of the period held with JPMorgan Chase as tri-party agent, were U.S. Treasury securities with various maturities to 10/31/2022 and the market value of those underlying securities was $102,002,703.	90,000,000

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Principal Amount		Value
	REPURCHASE AGREEMENTS—continued
$25,456,000	Interest in $4,000,000,000 joint repurchase agreement 0.10%, dated 11/30/2015 under which Credit Agricole CIB New York will repurchase securities provided as collateral for $4,000,011,111 on 12/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 11/15/2045 and the market value of those underlying securities was $4,080,011,398.	$25,456,000
50,000,000	Interest in $100,000,000 joint repurchase agreement 0.09%, dated 11/30/2015 under which HSBC Securities (USA), Inc. will repurchase securities provided as collateral for $100,000,250 on 12/1/2015. The securities provided as collateral at the end of the period held with JPMorgan Chase as tri-party agent, were U.S. Treasury securities maturing on 4/15/2028 and the market value of those underlying securities was $102,002,322.	50,000,000
200,000,000	Interest in $400,000,000 joint repurchase agreement 0.11%, dated 11/30/2015 under which Natixis Financial Products LLC will repurchase securities provided as collateral for $400,001,222 on 12/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 2/15/2043 and the market value of those underlying securities was $408,001,342.	200,000,000
50,000,000	Interest in $1,000,000,000 joint repurchase agreement 0.12%, dated 11/30/2015 under which Societe Generale, New York will repurchase securities provided as collateral for $1,000,003,333 on 12/1/2015. The securities provided as collateral at the end of the period held with BNY Mellon as tri-party agent, were U.S. Treasury securities with various maturities to 11/15/2044 and the market value of those underlying securities was $1,020,003,402.	50,000,000
	TOTAL REPURCHASE AGREEMENTS	665,456,000
	TOTAL INVESTMENTS—100.0% (AT AMORTIZED COST)3	871,309,693
	OTHER ASSETS AND LIABILITIES—NET-0.0%4	11,975
	TOTAL NET ASSETS—100%	$871,321,668

1	Discount rate(s) at time of purchase.
2	Floating rate notes with current rate(s) and next reset date(s) shown.
3	Also represents cost for federal tax purposes.
4	Assets, other than investments in securities, less liabilities. See Statement of Assets and Liabilities.

Note: The categories of investments are shown as a percentage of total net assets at November 30, 2015.

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Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below:

Level 1—quoted prices in active markets for identical securities.

Level 2—other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.). Also includes securities valued at amortized cost.

Level 3—significant unobservable inputs (including the Fund's own assumptions in determining the fair value of investments).

The inputs or methodology used for valuing securities are not an indication of the risk associated with investing in those securities.

As of November 30, 2015, all investments of the Fund are valued at amortized cost, which is considered a Level 2 input, in valuing the Fund's assets.

See Notes which are an integral part of the Financial Statements

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Financial Highlights

(For a Share Outstanding Throughout Each Period)

	Six Months Ended (unaudited) 11/30/2015	Year Ended May 31,
		2015	2014	2013	2012	2011
Net Asset Value, Beginning of Period	$1.00	$1.00	$1.00	$1.00	$1.00	$1.00
Income From Investment Operations:
Net investment income	—	—	—	—	—	—
Net realized gain on investments	0.00001	0.00001	0.00001	—	0.00001	0.00001
TOTAL FROM INVESTMENT OPERATIONS	0.00001	0.00001	0.00001	—	0.00001	0.00001
Less Distributions:
Distributions from net realized gain on investments	(0.0000)1	(0.0000)1	(0.0000)1	(0.0000)1	(0.0000)1	(0.0000)1
Net Asset Value, End of Period	$1.00	$1.00	$1.00	$1.00	$1.00	$1.00
Total Return2	0.00%3	0.00%3	0.00%3	0.00%3	0.00%3	0.00%3
Ratios to Average Net Assets:
Net expenses	0.10%4	0.08%	0.07%	0.16%	0.10%	0.19%
Net investment income	0.00%4	0.00%	0.00%	0.00%	0.00%	0.00%
Expense waiver/reimbursement5	1.02%4	1.00%	1.01%	0.92%	0.98%	0.89%
Supplemental Data:
Net assets, end of period (000 omitted)	$871,322	$1,596,707	$2,358,885	$2,549,875	$2,355,609	$1,445,337

1	Represents less than $0.0001.
2	Based on net asset value. Total returns for periods of less than one year are not annualized.
3	Represents less than 0.01%.
4	Computed on an annualized basis.
5	This expense decrease is reflected in both the net expense and the net investment income ratios shown above.

See Notes which are an integral part of the Financial Statements

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Statement of Assets and Liabilities

November 30, 2015 (unaudited)

Assets:
Investment in repurchase agreements	$665,456,000
Investment in securities	205,853,693
Total investment in securities, at amortized cost and fair value		$871,309,693
Income receivable		267,105
Receivable for shares sold		400
TOTAL ASSETS		871,577,198
Liabilities:
Payable for shares redeemed	117
Bank overdraft	17,973
Payable to adviser (Note 4)	74,589
Payable for transfer agent fee	78,473
Payable for Directors'/Trustees' fees (Note 4)	172
Payable for portfolio accounting fees	42,352
Payable for printing and postage	38,781
Accrued expenses (Note 4)	3,073
TOTAL LIABILITIES		255,530
Net assets for 871,321,318 shares outstanding		$871,321,668
Net Assets Consist of:
Paid-in capital		$871,321,332
Accumulated net realized gain on investments		336
TOTAL NET ASSETS		$871,321,668
Net Asset Value, Offering Price and Redemption Proceeds Per Share:
$871,321,668 ÷ 871,321,318 shares outstanding, no par value, unlimited shares authorized		$1.00

See Notes which are an integral part of the Financial Statements

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Statement of Operations

Six Months Ended November 30, 2015 (unaudited)

Investment Income:
Interest			$699,384
Expenses:
Investment adviser fee (Note 4)		$3,603,655
Administrative fee (Note 4)		564,258
Custodian fees		31,155
Transfer agent fee		801,191
Directors'/Trustees' fees (Note 4)		7,432
Auditing fees		21,952
Legal fees		9,795
Portfolio accounting fees		90,408
Distribution services fee (Note 4)		720,731
Other service fees (Note 2)		1,801,827
Share registration costs		142,183
Printing and postage		177,088
Taxes		27,082
Miscellaneous (Note 4)		40,348
TOTAL EXPENSES		8,039,105
Waivers and Reimbursement:
Waiver of investment adviser fee (Note 4)	$(3,603,655)
Waivers/reimbursement of other operating expenses (Notes 2 and 5)	(3,736,066)
TOTAL WAIVERS AND REIMBURSEMENT		(7,339,721)
Net expenses			699,384
Net investment income			—
Net realized gain on investments			1,736
Change in net assets resulting from operations			$1,736

See Notes which are an integral part of the Financial Statements

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Statement of Changes in Net Assets

	Six Months Ended (unaudited) 11/30/2015	Year Ended 5/31/2015
Increase (Decrease) in Net Assets
Operations:
Net investment income	$—	$—
Net realized gain on investments	1,736	12,040
CHANGE IN NET ASSETS RESULTING FROM OPERATIONS	1,736	12,040
Distributions to Shareholders:
Distributions from net realized gain on investments	(13,409)	(8,149)
Share Transactions:
Proceeds from sale of shares	1,479,516,536	3,100,554,250
Net asset value of shares issued to shareholders in payment of distributions declared	13,345	8,004
Cost of shares redeemed	(2,204,903,219)	(3,862,744,332)
CHANGE IN NET ASSETS RESULTING FROM SHARE TRANSACTIONS	(725,373,338)	(762,182,078)
Change in net assets	(725,385,011)	(762,178,187)
Net Assets:
Beginning of period	1,596,706,679	2,358,884,866
End of period	$871,321,668	$1,596,706,679

See Notes which are an integral part of the Financial Statements

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Notes to Financial Statements

November 30, 2015 (unaudited)

1. ORGANIZATION

Cash Trust Series, Inc. (the “Corporation”) is registered under the Investment Company Act of 1940, as amended (the “Act”), as an open-end management investment company. The Corporation consists of four portfolios. The financial statements included herein are only those of Federated Treasury Cash Series (the “Fund”), a diversified portfolio. The financial statements of the other portfolios are presented separately. The assets of each portfolio are segregated and a shareholder's interest is limited to the portfolio in which shares are held. Each portfolio pays its own expenses. The investment objective of the Fund is current income consistent with stability of principal and liquidity.

2. SIGNIFICANT ACCOUNTING POLICIES

The following is a summary of significant accounting policies consistently followed by the Fund in the preparation of its financial statements. These policies are in conformity with U.S. generally accepted accounting principles (GAAP).

Investment Valuation

Securities are valued at amortized cost. Under the amortized cost valuation method, an investment is valued initially at its cost as determined in accordance with GAAP. The Fund then adjusts the amount of interest income accrued each day over the term of the investment to account for any difference between the initial cost of the investment and the amount payable at its maturity. If amortized cost is determined not to approximate fair value, the value of the portfolio securities will be determined in accordance with the procedures described below.

The Directors have ultimate responsibility for determining the fair value of investments. The Directors have appointed a Valuation Committee (“Valuation Committee”) comprised of officers of the Fund, Federated Investment Management Company (“Adviser”) and certain of the Adviser's affiliated companies to assist in determining fair value of securities and in overseeing the comparison of amortized cost to market-based value. The Directors have also authorized the use of pricing services recommended by the Valuation Committee to provide fair value evaluations of the current value of certain investments for purposes of monitoring the relationship of market-based value and amortized cost. The Valuation Committee employs various methods for reviewing third-party pricing-service evaluations including periodic reviews of third-party pricing services' policies, procedures and valuation methods (including key inputs and assumptions), and review of price challenges by the Adviser based on recent market activity. In the event that market quotations and price evaluations are not available for an investment, the Valuation Committee determines the fair value of the investment in accordance with procedures adopted by the Directors. The Directors periodically review and approve the fair valuations made by the Valuation Committee and any changes made to the procedures.

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Repurchase Agreements

The Fund may invest in repurchase agreements for short-term liquidity purposes. It is the policy of the Fund to require the other party to a repurchase agreement to transfer to the Fund's custodian or sub-custodian eligible securities or cash with a market value (after transaction costs) at least equal to the repurchase price to be paid under the repurchase agreement. The eligible securities are transferred to accounts with the custodian or sub-custodian in which the Fund holds a “securities entitlement” and exercises “control” as those terms are defined in the Uniform Commercial Code. The Fund has established procedures for monitoring the market value of the transferred securities and requiring the transfer of additional eligible securities if necessary to equal at least the repurchase price. These procedures also allow the other party to require securities to be transferred from the account to the extent that their market value exceeds the repurchase price or in exchange for other eligible securities of equivalent market value.

The insolvency of the other party or other failure to repurchase the securities may delay the disposition of the underlying securities or cause the Fund to receive less than the full repurchase price. Under the terms of the repurchase agreement, any amounts received by the Fund in excess of the repurchase price and related transaction costs must be remitted to the other party.

The Fund may enter into repurchase agreements in which eligible securities are transferred into joint trading accounts maintained by the custodian or sub-custodian for investment companies and other clients advised by the Fund's Adviser and its affiliates. The Fund will participate on a pro rata basis with the other investment companies and clients in its share of the securities transferred under such repurchase agreements and in its share of proceeds from any repurchase or other disposition of such securities.

Repurchase agreements are subject to Master Netting Agreements which are agreements between the Fund and its counterparties that provide for the net settlement of all transactions and collateral with the Fund, through a single payment, in the event of default or termination. Amounts presented on the Portfolio of Investments and Statement of Assets and Liabilities are not net settlement amounts but gross. As indicated above, the cash or securities to be repurchased, as shown on the Portfolio of Investments, exceeds the repurchase price to be paid under the agreement reducing the net settlement amount to zero.

Investment Income, Gains and Losses, Expenses and Distributions

Investment transactions are accounted for on a trade-date basis. Realized gains and losses from investment transactions are recorded on an identified-cost basis. Interest income and expenses are accrued daily. Distributions to shareholders are recorded on the ex-dividend date. Distributions of net investment income, if any, are declared daily and paid monthly. For the six months ended November 30, 2015, unaffiliated third-party financial intermediaries waived $708,698 of transfer agent fees.

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Other Service Fees

The Fund may pay other service fees up to 0.25% of the average daily net assets of the Fund to unaffiliated financial intermediaries or to Federated Shareholder Services Company (FSSC) for providing services to shareholders and maintaining shareholder accounts. Subject to the terms described in the Expense Limitation note, FSSC may voluntarily reimburse the Fund for other service fees. In addition, unaffiliated third-party financial intermediaries may waive other service fees. This waiver can be modified or terminated at any time. For the six months ended November 30, 2015, unaffiliated third parties waived $1,801,827 of other services fees.

Premium and Discount Amortization

All premiums and discounts are amortized/accreted using the effective-interest-rate method.

Federal Taxes

It is the Fund's policy to comply with the Subchapter M provision of the Internal Revenue Code and to distribute to shareholders each year substantially all of its income. Accordingly, no provision for federal income tax is necessary. As of and during the six months ended November 30, 2015, the Fund did not have a liability for any uncertain tax positions. The Fund recognizes interest and penalties, if any, related to tax liabilities as income tax expense in the Statement of Operations. As of November 30, 2015, tax years 2012 through 2015 remain subject to examination by the Fund's major tax jurisdictions, which include the United States of America, the state of Maryland and the Commonwealth of Pennsylvania.

Other Taxes

As an open-end management investment company incorporated in the state of Maryland but domiciled in the Commonwealth of Pennsylvania, the Fund is subject to the Pennsylvania Franchise Tax. This franchise tax is assessed annually on the value of the Fund, as represented by average net assets for the tax year.

When-Issued and Delayed-Delivery Transactions

The Fund may engage in when-issued or delayed-delivery transactions. The Fund records when-issued securities on the trade date and maintains security positions such that sufficient liquid assets will be available to make payment for the securities purchased. Securities purchased on a when-issued or delayed-delivery basis are marked to market daily and begin earning interest on the settlement date. Losses may occur on these transactions due to changes in market conditions or the failure of counterparties to perform under the contract.

Other

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts of assets, liabilities, expenses and revenues reported in the financial statements. Actual results could differ from those estimated. The Fund applies Investment Company accounting and reporting guidance.

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3. CAPITAL STOCK

The following table summarizes capital stock activity:

	Six Months Ended 11/30/2015	Year Ended 5/31/2015
Shares sold	1,479,516,536	3,100,554,250
Shares issued to shareholders in payment of distributions declared	13,345	8,004
Shares redeemed	(2,204,903,219)	(3,862,744,332)
NET CHANGE RESULTING FROM FUND SHARE TRANSACTIONS	(725,373,338)	(762,182,078)

4. INVESTMENT ADVISER FEE AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Adviser Fee

The advisory agreement between the Fund and the Adviser provides for an annual fee equal to 0.50% of the Fund's average daily net assets. Subject to the terms described in the Expense Limitation note, the Adviser may voluntarily choose to waive any portion of its fee and/or reimburse certain operating expenses of the Fund. For the six months ended November 30, 2015, the Adviser voluntarily waived its entire fee of $3,603,655 and voluntarily reimbursed $504,810 of other operating expenses.

Administrative Fee

Federated Administrative Services (FAS), under the Administrative Services Agreement, provides the Fund with administrative personnel and services. For purposes of determining the appropriate rate breakpoint, “Investment Complex” is defined as all of the Federated Funds subject to a fee under the Administrative Services Agreement. The fee paid to FAS is based on the average daily net assets of the Investment Complex as specified below, plus certain out-of-pocket expenses:

Administrative Fee	Average Daily Net Assets of the Investment Complex
0.150%	on the first $5 billion
0.125%	on the next $5 billion
0.100%	on the next $10 billion
0.075%	on assets in excess of $20 billion

Subject to the terms described in the Expense Limitation note, FAS may voluntarily choose to waive any portion of its fee. For the six months ended November 30, 2015, the annualized fee paid to FAS was 0.078% of average daily net assets of the Fund.

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Distribution Services Fee

The Fund has adopted a Distribution Plan (the “Plan”) pursuant to Rule 12b-1 under the Act. Under the terms of the Plan, the Fund will reimburse Federated Securities Corp. (FSC), the principal distributor, from the daily net assets of the Fund to finance activities intended to result in the sale of these shares. The Plan provides that the Fund may incur distribution expenses of up to 0.35% of average daily net assets, annually, to reimburse FSC. Subject to the terms described in the Expense Limitation note, FSC may voluntarily choose to waive any portion of its fee. For the six months ended November 30, 2015, FSC voluntarily waived its entire fee of $720,731. When FSC receives fees, it may pay some or all of them to financial intermediaries whose customers purchase shares.

Expense Limitation

Due to the possibility of changes in market conditions and other factors, there can be no assurance that the level of waivers/reimbursement/reduction of Fund expenses reflected in the financial highlights will be maintained in the future. However, the Adviser and certain of its affiliates (which may include FSC, FAS and FSSC) on their own initiative have agreed to waive certain amounts of their respective fees and/or reimburse expenses. Total annual fund operating expenses (as shown in the financial highlights, excluding extraordinary expenses and proxy-related expenses paid by the Fund, if any) paid by the Fund's Shares (after the voluntary waivers and/or reimbursements) will not exceed 1.05% (the “Fee Limit”), up to but not including the later of (the “Termination Date”): (a) August 1, 2016; or (b) the date of the Fund's next effective Prospectus. While the Adviser and its applicable affiliates currently do not anticipate terminating or increasing these arrangements prior to the Termination Date, these arrangements may only be terminated or the Fee Limit increased prior to the Termination Date with the agreement of the Directors.

General

Certain Officers and Directors of the Fund are Officers and Directors or Trustees of certain of the above companies. To efficiently facilitate payment, Directors'/Trustees' fees and certain expenses related to conducting meetings of the Directors/Trustees and other miscellaneous expenses are paid by an affiliate of the Adviser which in due course are reimbursed by the Fund. Such expenses may be included in Accrued and Miscellaneous Expenses on the Statement of Assets and Liabilities and Statement of Operations, respectively.

5. LINE OF CREDIT

The Fund participates in a $100,000,000 unsecured, uncommitted revolving line of credit (LOC) agreement with PNC Bank. The LOC was made available for extraordinary or emergency purposes, primarily for financing redemption payments. Borrowings are charged interest at a rate offered to the Fund by PNC Bank at the time of the borrowing. As of November 30, 2015, there were no outstanding loans. During the six months ended November 30, 2015, the Fund did not utilize the LOC.

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6. INTERFUND LENDING

Pursuant to an Exemptive Order issued by the Securities and Exchange Commission (SEC), the Fund, along with other funds advised by subsidiaries of Federated Investors, Inc., may participate in an interfund lending program. This program provides an alternative credit facility allowing the Fund to borrow from other participating affiliated funds. As of November 30, 2015, there were no outstanding loans. During the six months ended November 30, 2015, the program was not utilized.

7. REGULATORY MATTERS

On July 23, 2014, the SEC voted to amend the rules under the Act which currently govern the operations of the Fund. A significant change resulting from these amendments will be a requirement that institutional prime funds (i.e. not government or retail as defined in the amendments), transact fund shares based on a market-based Net Asset Value (NAV). This change does not impact government money market funds, and because it is anticipated that the Fund will constitute a government money market fund under the new rules, the Fund will be permitted to continue transacting fund shares at an NAV calculated using the amortized cost valuation method. Among additional disclosure and other requirements, the amendments also will permit a money market fund, or, in certain circumstances, require a money market fund (other than a government money market fund, like the Fund, which satisfies the requirements of the amendments) to impose liquidity fees on redemptions, and permit a money market fund to limit (or gate) redemptions for up to 10 business days in any 90-day period. The amendments have staggered compliance dates. Compliance with a majority of these amendments will be required on October 14, 2016, two years after the effective date for the rule amendments. The degree to which a money market fund will be impacted by the rule amendments will depend upon the type of fund and type of investors (retail or institutional). At this time, management is evaluating the implications of these amendments and their impact to the Fund's operations, financial statements and accompanying notes.

8. SUBSEQUENT EVENTS

On December 11, 2015, Federated Trust for U.S. Treasury Obligations acquired all or substantially all of the assets of the Fund in complete liquidation and termination of the Fund.

Management has evaluated subsequent events through the date the financial statements were issued and determined that no additional events occurred that require disclosure.

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Shareholder Expense Example (unaudited)

As a shareholder of the Fund, you incur ongoing costs, including management fees and to the extent applicable, distribution (12b-1) fees and/or other service fees and other Fund expenses. This Example is intended to help you to understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds. It is based on an investment of $1,000 invested at the beginning of the period and held for the entire period from June 1, 2015 to November 30, 2015.

ACTUAL EXPENSES

The first section of the table below provides information about actual account values and actual expenses. You may use the information in this section, together with the amount you invested, to estimate the expenses that you incurred over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number in the first section under the heading entitled “Expenses Paid During Period” to estimate the expenses attributable to your investment during this period.

HYPOTHETICAL EXAMPLE FOR COMPARISON PURPOSES

The second section of the table below provides information about hypothetical account values and hypothetical expenses based on the Fund's actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund's actual return. Thus, you should not use the hypothetical account values and expenses to estimate the actual ending account balance or your expenses for the period. Rather, these figures are required to be provided to enable you to compare the ongoing costs of investing in the Fund with other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

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Please note that the expenses shown in the table are meant to highlight your ongoing costs only. Therefore, the second section of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds.

	Beginning Account Value 6/1/2015	Ending Account Value 11/30/2015	Expenses Paid During Period1,2
Actual	$1,000	$1,000.00	$0.50
Hypothetical (assuming a 5% return before expenses)	$1,000	$1,024.50	$0.51

1

Expenses are equal to the Fund's annualized net expense ratio of 0.10%, multiplied by the average account value over the period, multiplied by 183/366 (to reflect the one-half-year period).

2

Actual and Hypothetical expenses paid during the period utilizing the Fund's current Fee Limit of 1.05% (as reflected in the Notes to Financial Statements, Note 4 under Expense Limitation), multiplied by the average account value over the period, multiplied by 183/366 (to reflect expenses paid as if they had been in effect throughout the most recent one-half-year period) would be $5.25 and $5.30, respectively.

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Evaluation and Approval of Advisory Contract–May 2015

Federated Treasury Cash Series (the “Fund”)

Following a review and recommendation of approval by the Fund's independent directors, the Fund's Board reviewed and approved at its May 2015 meetings the Fund's investment advisory contract for an additional one-year term. The Board's decision regarding the contract reflects the exercise of its business judgment on whether to continue the existing arrangements.

In this connection, the Federated Funds' Board had previously appointed a Senior Officer, whose duties include specified responsibilities relating to the process by which advisory fees are to be charged to a Federated fund. The Senior Officer has the authority to retain consultants, experts, or staff as may be reasonably necessary to assist in the performance of his duties, reports directly to the Board, and may be terminated only with the approval of a majority of the independent members of the Board. The Senior Officer prepared and furnished to the Board an independent, written evaluation that covered topics discussed below (the “Evaluation”). The Board considered that Evaluation, along with other information, in deciding to approve the advisory contract.

The Board is also familiar with and considered judicial decisions concerning allegedly excessive investment advisory fees, which have indicated that the following factors may be relevant to an Adviser's fiduciary duty with respect to its receipt of compensation from a fund: the nature and quality of the services provided by the Adviser to a fund and its shareholders, including the performance and expenses of the fund and of comparable funds; the Adviser's cost of providing the services, including the profitability to the Adviser of providing advisory services to a fund; the extent to which the Adviser may realize “economies of scale” as a fund grows larger and, if such economies of scale exist, whether they have been shared with a fund and its shareholders or the family of funds; any “fall-out financial benefits” that accrue to the Adviser because of its relationship with a fund (including research services received from brokers that execute fund trades and any fees paid to affiliates of the Adviser for services rendered to a fund); comparative fee structures, including a comparison of fees paid to the Adviser with those paid by similar funds; and the extent of care, conscientiousness and independence with which the Board members perform their duties and their expertise, including whether they are fully informed about all facts the Board deems relevant to its consideration of the Adviser's services and fees. The Board noted that SEC disclosure requirements regarding the basis for the Board's approval of the Fund's advisory contract generally track the factors listed above. Consistent with these judicial decisions and SEC disclosure requirements, the Board also considered management fees

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charged to institutional and other clients of the Adviser for what might be viewed as like services. The Board was aware of these factors and was guided by them in its review of the Fund's advisory contract to the extent it considered them to be appropriate and relevant, as discussed further below.

The Board considered and weighed these circumstances in light of its substantial accumulated experience in governing the Fund and working with Federated on matters relating to the Federated funds, and was assisted in its deliberations by independent legal counsel. Throughout the year, and in connection with its May meetings, the Board requested and received substantial and detailed information about the Fund and the Federated organization that was in addition to the extensive materials that comprise and accompany the Senior Officer's Evaluation. Federated provided much of this information at each regular meeting of the Board, and furnished additional substantial information in connection with the May meeting at which the Board's formal review of the advisory contract occurred. At this May meeting, senior management of the Adviser also met with the independent directors and their counsel to discuss the materials presented and any other matters thought relevant by the Adviser or the directors. Between regularly scheduled meetings, the Board also received information on particular matters as the need arose. Thus, the Board's consideration of the advisory contract included review of the Senior Officer's Evaluation, accompanying data and additional information covering such matters as: the Adviser's investment philosophy, revenue, profitability, personnel and processes; investment and operating strategies; the Fund's short- and long-term performance (in absolute terms, both on a gross basis and net of expenses, as well as in relationship to its particular investment program and certain competitor or “peer group” funds and/or other benchmarks, as appropriate), and comments on the reasons for performance; the Fund's investment objectives; the Fund's expenses (including the advisory fee itself and the overall expense structure of the Fund, both in absolute terms and relative to similar and/or competing funds, with due regard for contractual or voluntary expense limitations); the use and allocation of brokerage commissions derived from trading the Fund's portfolio securities (if any); and the nature, quality and extent of the advisory and other services provided to the Fund by the Adviser and its affiliates. The Board also considered the preferences and expectations of Fund shareholders; the entrepreneurial risk assumed by the Adviser in sponsoring the funds; the continuing state of competition in the mutual fund industry and market practices; the range of comparable fees for similar funds in the mutual fund industry; the Fund's relationship to the Federated family of funds which include a comprehensive array of funds with different investment objectives, policies and strategies which are available for exchange without the incurrence of additional sales charges; compliance and audit reports concerning the Federated funds and the Federated companies that service them (including communications from regulatory agencies), as well as Federated's responses to any issues raised therein; and relevant developments in

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the mutual fund industry and how the Federated funds and/or Federated are responding to them. The Board's evaluation process is evolutionary. The criteria considered and the emphasis placed on relevant criteria change in recognition of changing circumstances in the mutual fund marketplace.

While mindful that courts have cautioned against giving such comparisons too much weight, the Board has found the use of comparisons of the Fund's fees and expenses to other mutual funds with comparable investment programs to be relevant. In this regard, the Board was presented with, and considered, information regarding the contractual advisory fee rates, net advisory fee rates and total expense ratios relative to a fund's peers. The Board focused on comparisons with other similar mutual funds more heavily than non-mutual fund products or services because it is believed that they are more relevant. For example, other mutual funds are the products most like the Fund, they are readily available to Fund shareholders as alternative investment vehicles, and they are the type of investment vehicle in fact chosen and maintained by the Fund's investors. The range of their fees and expenses therefore appears to be a relevant indicator of what consumers have found to be reasonable in the precise marketplace in which the Fund competes.

It was noted in the materials for the Board meeting that for the period covered by the Evaluation, the Fund's investment advisory fee was waived in its entirety. The Board reviewed the contractual advisory fee rate, net advisory fee rate and other expenses of the Fund with the Adviser and noted the position of the Fund's fee rates relative to its peers. In this regard, the Board noted that the contractual advisory fee rate was above the median of the relevant peer group, but the Board noted that the investment advisory fee was waived in its entirety and that the overall expense structure of the Fund remained competitive.

By contrast, the Senior Officer has reviewed Federated's fees for providing advisory services to products outside the Federated family of funds (e.g., institutional and separate accounts and sub-adviser services). He concluded that mutual funds and institutional accounts are inherently different products. Those differences include, but are not limited to, different types of targeted investors; being subject to different laws and regulations; different legal structures; different average account sizes and portfolio management techniques made necessary by different cash flows and different associated costs; and the time spent by portfolio managers and their teams, funds financial services, legal, compliance and risk management in reviewing securities pricing, addressing different administrative responsibilities, addressing different degrees of risk associated with management and a variety of different costs. The Senior Officer did not consider these fee schedules to be determinative in judging the appropriateness of mutual fund advisory fees.

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The Fund's ability to deliver competitive performance when compared to its peer group was also deemed to be relevant by the Board as a useful indicator of how the Adviser is executing the Fund's investment program, which in turn was one of the Board's considerations in reaching a conclusion that the nature, extent, and quality of the Adviser's investment management services were such as to warrant continuation of the advisory contract.

The Senior Officer reviewed information compiled by Federated, using data supplied by independent fund ranking organizations, regarding the performance of, and fees charged by, other mutual funds, noting his view that comparisons to fund peer groups may be helpful, though not conclusive, in judging the reasonableness of the proposed fees. The Board considered, in evaluating such comparisons, that in some cases individual funds may exhibit significant and unique differences in their objectives and management techniques when compared to other funds within an industry peer group.

The Fund's performance was above the median of the relevant peer group for the one-year period covered by the Evaluation.

The Board also received financial information about Federated, including information regarding the compensation and benefits Federated derived from its relationships with the Federated funds. This information covered not only the fees under the advisory contracts, but also fees received by Federated's subsidiaries for providing other services to the Federated funds under separate contracts (e.g., for serving as the Federated funds' administrator). The information also detailed any indirect benefit Federated may derive from its receipt of research services from brokers who execute Federated fund trades. In addition, the Board considered the fact that, in order for a fund to be competitive in the marketplace, Federated and its affiliates frequently waived fees and/or reimbursed expenses and have disclosed to fund investors and/or indicated to the Board their intention to do so in the future, where appropriate. Moreover, the Board receives regular reporting as to the institution, adjustment or elimination of these voluntary waivers.

In addition, over the past two years, following discussions regarding the Senior Officer's recommendations, Federated made meaningful reductions to the contractual advisory fees for several Funds. In May 2014, the Senior Officer recommended that Federated review the fee structures of its money market funds to determine whether it would be appropriate to consider alternative pricing structures. Federated has combined that review with its consideration of the re-structuring of its money market fund product line in response to the recently adopted amendments to Rule 2a-7 under the Investment Company Act of 1940, as amended (the “1940 Act”).

At the Board meeting in May 2015, following previous recommendations of the Senior Officer, Federated proposed, and the Board approved, reductions in the contractual advisory fees of certain other Funds.

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Federated furnished information, requested by the Senior Officer, that reported revenues on a fund-by-fund basis and made estimates of the allocation of expenses on a fund-by-fund basis, using allocation methodologies specified by the Senior Officer. The Senior Officer noted that, while these cost allocation reports apply consistent allocation processes, the inherent difficulties in allocating costs continues to cause the Senior Officer to question the precision of the process and to conclude that such reports may be unreliable, since a single change in an allocation estimate may dramatically alter the resulting estimate of cost and/or profitability of a fund and may produce unintended consequences. The allocation information, including the Senior Officer's view that fund-by-fund estimations may be unreliable, was considered in the analysis by the Board.

The Board and the Senior Officer also reviewed information compiled by Federated comparing profitability information for Federated to other publicly held fund management companies. In this regard, the Senior Officer concluded that Federated's profit margins did not appear to be excessive. The Senior Officer also noted that Federated appeared financially sound, with the resources to fulfill its obligations under its contracts with the Funds.

The Senior Officer's Evaluation also discussed the notion of possible realization of “economies of scale” as a fund grows larger. The Board considered in this regard that the Adviser has made significant and long-term investments in areas that support all of the Federated family of funds, such as personnel and processes for the portfolio management, shareholder services, compliance, internal audit, and risk management functions; and systems technology; and that the benefits of these efforts (as well as any economies of scale, should they exist) were likely to be enjoyed by the fund family as a whole. Federated, as it does throughout the year, and again in connection with the Board's review, furnished information relative to revenue sharing or adviser paid fees. Federated and the Senior Officer noted that this information should be viewed to determine if there was an incentive to either not apply breakpoints or to apply breakpoints at higher levels and should not be viewed to determining the appropriateness of advisory fees, because it would represent marketing and distribution expenses. Finally, the Board also noted the absence of any applicable regulatory or industry guidelines on this subject, which (as discussed in the Senior Officer's Evaluation) is compounded by the lack of any common industry practice or general pattern with respect to structuring fund advisory fees with “breakpoints” that serve to reduce the fee as the fund attains a certain size.

The Senior Officer noted that, subject to the comments and recommendations made within his Evaluation, his observations and the information accompanying the Evaluation supported a finding by the Board that the management fees for each of the funds were reasonable. Under these circumstances, no objection was raised to the continuation of, the Fund's advisory contract.

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In its decision to continue an existing investment advisory contract, the Board was mindful of the potential disruptions of the Fund's operations and various risks, uncertainties and other effects that could occur as a result of a decision to terminate or not renew an advisory contract. In particular, the Board recognized that many shareholders have invested in the Fund on the strength of the Adviser's industry standing and reputation and with the expectation that the Adviser will have a continuing role in providing advisory services to the Fund. Thus, the Board's approval of the advisory contract reflected the fact that it is the shareholders who have effectively selected the Adviser by virtue of having invested in the Fund. The Board concluded that, in light of the factors discussed above, including the nature, quality and scope of the services provided to the Fund by the Adviser and its affiliates, continuation of the advisory contract was appropriate.

The Board based its decision to approve the advisory contract on the totality of the circumstances and relevant factors and with a view to past and future long-term considerations. Not all of the factors and considerations identified above were necessarily relevant to the Fund, nor did the Board consider any one of them to be determinative. With respect to the factors that were relevant, the Board's decision to approve the contract reflects its determination that Federated's performance and actions provided a satisfactory basis to support the decision to continue the existing arrangements.

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Voting Proxies on Fund Portfolio Securities

A description of the policies and procedures that the Fund uses to determine how to vote proxies, if any, relating to securities held in the Fund's portfolio is available, without charge and upon request, by calling 1-800-341-7400. A report on “Form N-PX” of how the Fund voted any such proxies during the most recent 12-month period ended June 30 is available via the Proxy Voting Record (Form N-PX) link associated with the Fund and share class name at www.FederatedInvestors.com/FundInformation. Form N-PX filings are also available at the SEC's website at www.sec.gov.

Quarterly Portfolio Schedule

The Fund files with the SEC a complete schedule of its portfolio holdings, as of the close of the first and third quarters of its fiscal year, on “Form N-Q.” These filings are available on the SEC's website at www.sec.gov and may be reviewed and copied at the SEC's Public Reference Room in Washington, DC. (Call 1-800-SEC-0330 for information on the operation of the Public Reference Room.) You may also access this information via the link to the Fund and share class name at www.FederatedInvestors.com/FundInformation.

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Mutual funds are not bank deposits or obligations, are not guaranteed by any bank and are not insured or guaranteed by the U.S. government, the Federal Deposit Insurance Corporation, the Federal Reserve Board or any other government agency. Investment in mutual funds involves investment risk, including the possible loss of principal. Although money market funds seek to maintain a stable net asset value of $1.00 per share, there is no assurance that they will be able to do so.

This Report is authorized for distribution to prospective investors only when preceded or accompanied by the Fund's Prospectus, which contains facts concerning its objective and policies, management fees, expenses and other information.

IMPORTANT NOTICE ABOUT FUND DOCUMENT DELIVERY    

In an effort to reduce costs and avoid duplicate mailings, the Fund(s) intend to deliver a single copy of certain documents to each household in which more than one shareholder of the Fund(s) resides (so-called “householding”), as permitted by applicable rules. The Fund's “householding” program covers its/their Prospectus and Statement of Additional Information, and supplements to each, as well as Semi-Annual and Annual Shareholder Reports and any Proxies or information statements. Shareholders must give their written consent to participate in the “householding” program. The Fund is also permitted to treat a shareholder as having given consent (“implied consent”) if (i) shareholders with the same last name, or believed to be members of the same family, reside at the same street address or receive mail at the same post office box, (ii) the Fund gives notice of its intent to “household” at least sixty (60) days before it begins “householding” and (iii) none of the shareholders in the household have notified the Fund(s) or their agent of the desire to “opt out” of “householding.” Shareholders who have granted written consent, or have been deemed to have granted implied consent, can revoke that consent and opt out of “householding” at any time: shareholders who purchased shares through an intermediary should contact their representative; other shareholders may call the Fund at 1-800-341-7400.

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Federated Treasury Cash Series

Federated Investors Funds
4000 Ericsson Drive
Warrendale, PA 15086-7561

Contact us at FederatedInvestors.com
or call 1-800-341-7400.

Federated Securities Corp., Distributor

CUSIP 147551402

0122607 (1/16)

Federated is a registered trademark of Federated Investors, Inc.
2016 ©Federated Investors, Inc.

Item 2. Code of Ethics

Not Applicable

Item 3. Audit Committee Financial Expert

Not Applicable

Item 4. Principal Accountant Fees and Services

Not Applicable

Item 5. Audit Committee of Listed Registrants

Not Applicable

Item 6. Schedule of Investments

(a) The registrant’s Schedule of Investments is included as part of the Report to Stockholders filed under Item 1 of this form.

(b) Not Applicable; Fund had no divestments during the reporting period covered since the previous Form N-CSR filing.

Item 7. Disclosure of Proxy Voting Policies and Procedures for Closed-End Management Investment Companies

Not Applicable

Item 8. Portfolio Managers of Closed-End Management Investment Companies

Not Applicable

Item 9. Purchases of Equity Securities by Closed-End Management Investment Company and Affiliated Purchasers

Not Applicable

Item 10. Submission of Matters to a Vote of Security Holders

No Changes to Report

Item 11. Controls and Procedures

(a) The registrant’s President and Treasurer have concluded that the

registrant’s disclosure controls and procedures (as defined in rule 30a-3(c) under the Act) are effective in design and operation and are sufficient to form the basis of the certifications required by Rule 30a-(2) under the Act, based on their evaluation of these disclosure controls and procedures within 90 days of the filing date of this report on Form N-CSR.

(b) There were no changes in the registrant’s internal control over financial reporting (as defined in rule 30a-3(d) under the Act) during the second fiscal quarter of the period covered by this report that have materially affected, or are reasonably likely to materially affect, the registrant’s internal control over financial reporting.

Item 12. Exhibits

(a)(1) Code of Ethics- Not Applicable to this Report.

(a)(2) Certifications of Principal Executive Officer and Principal Financial Officer.

(a)(3) Not Applicable.

(b) Certifications pursuant to 18 U.S.C. Section 1350.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Registrant Cash Trust Series, Inc.

By /S/ Lori A. Hensler

Lori A. Hensler

Principal Financial Officer

Date January 25, 2016

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

By /S/ J. Christopher Donahue

J. Christopher Donahue

Principal Executive Officer

Date January 25, 2016

By /S/ Lori A. Hensler

Lori A. Hensler

Principal Financial Officer

Date January 25, 2016