Putnam Money Market Fund (PDDXX) 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

Investment Company Act file number: (811-02608)

Exact name of registrant as specified in charter: Putnam Money Market Fund

Address of principal executive offices: One Post Office Square, Boston, Massachusetts 02109

Name and address of agent for service: Robert T. Burns, Vice President
One Post Office Square
Boston, Massachusetts 02109

Copy to:         John W. Gerstmayr, Esq.
Ropes & Gray LLP
800 Boylston Street
Boston, Massachusetts 02199-3600

Registrant’s telephone number, including area code: (617) 292-1000

Date of fiscal year end: September 30, 2012

Date of reporting period: October 1, 2011 — March 31, 2012

Item 1. Report to Stockholders:

The following is a copy of the report transmitted to stockholders pursuant to Rule 30e-1 under the Investment Company Act of 1940:

Putnam
Money Market
Fund

Semiannual report
3 | 31 | 12

Message from the Trustees	1
About the fund	2
Performance snapshot	4
Interview with your fund’s portfolio managers	5
Your fund’s performance	10
Your fund’s expenses	11
Terms and definitions	13
Other information for shareholders	14
Financial statements	15

Consider these risks before investing: Money market funds are not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other governmental agency. Although the fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in this fund.

Message from the Trustees

Dear Fellow Shareholder:

After a quarter century of trending lower, U.S. Treasury rates have shown some upward movement on signs of an improving economy during the past few months. Greece’s successful debt restructuring and some better-than-expected economic data in the United States have helped to coax investors off the sidelines and back into the markets. While we believe the historic bull market in government debt is likely near its close, fixed-income markets today continue to offer myriad investing opportunities.

Investing in fixed-income markets, however, requires particular expertise and the capacity for deep security-level research. We believe Putnam’s veteran fixed-income team is well suited to that task, and offers a long-term track record of uncovering attractive opportunities across all sectors of the bond markets.

In other news, please join us in welcoming the return of Elizabeth T. Kennan to the Board of Trustees. Dr. Kennan, who served as a Trustee from 1992 until 2010, has rejoined the Board, effective January 1, 2012. Dr. Kennan is a Partner of Cambus-Kenneth Farm (thoroughbred horse breeding and general farming), and is also President Emeritus of Mount Holyoke College.

We would also like to take this opportunity to welcome new shareholders to the fund and to thank all of our investors for your continued confidence in Putnam.

About the fund

Seeking to offer accessibility and current income with relatively low risk

For most people, keeping part of their savings in an easily accessible place is an essential part of an investment plan. Putnam Money Market Fund can play a valuable role in many investors’ portfolios because it seeks to provide stability of principal and liquidity to meet short-term needs. In addition, the fund aims to provide investors with current income at short-term rates.

Because it invests in high-quality short-term money market instruments, the fund’s risk of losing principal may be lower than that of other funds. It typically invests in securities that are rated in the highest or second-highest category of at least one nationally recognized rating service. The fund seeks as high a rate of current income as Putnam Management believes is consistent with preservation of capital and maintenance of liquidity. Money market fund yields typically rise and fall along with short-term interest rates. Money market funds may not track rates exactly, however, as securities in these funds mature and are replaced with newer instruments earning the most current interest rates.

Whether you want to earmark money for near-term expenses or future investment opportunities, or just stow away cash for an unforeseen “rainy day,” this fund can be an appropriate choice.

Types of money market securities

Money market securities are issued by governments, government agencies, financial institutions, and established non-financial companies. Securities your fund invests in include:

Commercial paper Short-term unsecured loans issued by large corporations, typically for financing accounts receivable and inventories

Bank certificates of deposit Direct obligations of the issuing commercial bank or savings and loan association

Repurchase agreements (repos) Contracts in which one party sells a security to another party and agrees to buy it back later at a specified price; acts in economic terms as a secured loan

Government securities Direct short-term obligations of governments or government agencies; for example, U.S. Treasury bills

Variable-rate demand notes (VRDNs) Floating-rate securities with a long-term maturity, usually 20 or 30 years, that carry a coupon that resets every one or seven days, making them eligible for purchase by money market mutual funds.

2 3

Current performance may be lower or higher than the quoted past performance, which cannot guarantee future results. Share price, principal value, and return will fluctuate, and you may have a gain or a loss when you sell your shares. Performance of class A shares assumes reinvestment of distributions and does not account for taxes. Class A shares do not bear an initial sales charge. Yield reflects current performance more closely than total return. See pages 5 and 10–11 for additional performance information. For a portion of the periods, the fund had expense limitations, without which returns would have been lower. Due to market volatility, current performance may be higher or lower than performance shown. To obtain the most recent month-end performance, visit putnam.com.

* Returns for the six-month period are not annualized, but cumulative.

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Interview with your fund’s portfolio managers

What was the investment backdrop like during the six months ended March 31, 2012?

Joanne: The six months was a tale of two halves, with investors gaining confidence as the reporting period progressed. Uncertainty remained high in the early months as the large macroeconomic challenges that dominated headlines throughout 2011 continued to weigh on investor confidence. Treasury rates in the United States declined slightly amid solid demand from risk-averse investors, while discussions over reducing the size of the federal deficit continued to take center stage heading into an election year. Outside the United States, little progress was made in the European sovereign debt situation despite ongoing negotiations.

By the first quarter of 2012, however, the U.S. economy had surprised on the upside. Economic data including housing, jobs, consumer confidence, and spending were either stable or slowly improving — suggesting that the U.S. economy, and the global economic outlook for that matter, might not be as bleak as first thought. Signs of a U.S. recovery were welcome news amid Europe’s clear economic deceleration and China’s more measured slowdown. The positive U.S. economic reports were enough to tempt cautious investors who had waited out the uncertainty in lower-risk investments to shift assets into higher-risk strategies, such as equities and high-yield bonds. Treasury rates rose during the risk rally to attract interest amid the stronger economic results.

This comparison shows your fund’s performance in the context of broad market indexes for the six months ended 3/31/12. See pages 4 and 10–11 for additional fund performance information. Index descriptions can be found on page 13.

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How did Putnam Money Market Fund perform in this environment?

Jonathan: The reporting period was a challenging time for investors focused on the short end of the yield curve. The Federal Reserve [Fed] remained firm in its resolve to hold its benchmark federal funds rate steady in the 0%-to-0.25% range to promote growth and maintain liquidity in the financial system. The near-zero rates have hovered at this level for over three years, resulting in historically low returns and yields on money market securities. With its conservative, high-quality focus, the fund delivered performance that was in line with this interest-rate environment.

What were the biggest concerns weighing on the money markets during the reporting period?

Joanne: Low interest rates, the eurozone debt crisis, and further reforms to money market funds preoccupied money-market investors during the period.

Commentary contained in the Fed minutes indicated that the Board of Governors intends to maintain interest rates at their present levels well into 2014 and that it is unlikely to embark on another round of asset purchases [known as QE1 and QE2] unless growth stalls or inflation is less than its 2.0% target. Persistently low rates offer little opportunity for income, but money markets have proven resilient over the past several years as they continue to be a stable and liquid investment alternative with over $2.4 trillion in assets.

During the fourth quarter of 2011, concerns over economic issues in Europe continued to weigh on investor’s minds. Greece remained the focal point as the country sought legislative reforms to control its spending in order to receive further funding from the European Central Bank [ECB]. Many banks hold billions in the sovereign debt of Greece, Spain, Portugal, and other struggling countries, which poses a risk should those countries be faced with default. To ease the pressure from

Allocations are represented as a percentage of portfolio value. Summary information may differ from the portfolio schedule included in the financial statements due to the inclusion of derivative securities and the exclusion of as-of trades, if any,and the use of different classifications of securities for presentation purposes. Holdings and allocations may vary over time.

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these situations, the ECB enacted the Long Term Refinancing Operation [LTRO], which has helped inject liquidity into the European banking system and, in turn, helped to boost investor confidence.

There has been increased discussion in recent months about the Securities and Exchange Commission [SEC] proposing additional regulations to reduce the susceptibility of money market funds to liquidity runs. These new proposals include requirements for capital buffers, redemption restrictions, and possibly variable-rate net asset values. Although there has been much debate over what form these potential new regulations will take, the SEC has yet to announce any formal action, but is expected to do so over the next several months.

With interest rates pinned down at such low levels for the period, where did you find your best investment opportunities?

Jonathan: Over the course of the period, we found opportunities further out on the money market yield curve, allowing us to extend maturities in the portfolio to take advantage of attractive rates for longer periods of time. The ECB’s massive LTRO has added much needed liquidity to the eurozone banking system and bolstered market sentiment. Given the improving credit picture for certain issuers, we felt more comfortable selectively adding to the fund’s credit exposure by investing in securities issued in Canada, Australia, and the more economically viable Nordic countries in northern Europe. As always, we remained diligent in our fundamental credit research process to avoid exposure to securities that might pose a risk to the fund.

Also, in late February and early March, the U.S. Treasury issued new supply, and rates backed up across the Treasury yield curve. At this time, we opportunistically added to the fund’s position in Treasury bills and notes. We have maintained significant allocations — although lower than in the beginning of the period — to high-quality money market securities, such as repurchase agreements that are collateralized by government securities.

On March 31, 2012, the 7-day yield [with the fund’s expense limitation] was 0.01%, and the portfolio’s WAM [weighted average maturity] was 52 days.

Which fund holdings exemplified your strategy during the period?

Joanne: During the period, the fund was exposed to large, creditworthy banks, such as JPMorgan Chase, Bank of Nova Scotia, and National Australia Bank. Looking at underlying bank fundamentals, we believe we see a relatively improving picture. Asset-quality measures are showing improving trends. Profits are being retained and are helping to build capital. These positive developments are somewhat offset by the banks’ underlying revenue weakness with soft loan demand, pressured interest margins, lower capital markets volume, and ongoing regulatory pressure on fee business. The European sovereign debt stress remains an influence on our overall bank positioning, and we have limited these exposures.

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U.S. growth appears to be improving but the Fed remains committed to its accommodative monetary policy for the foreseeable future. What are the implications of this policy for money market investors?

Jonathan: We believe the U.S. economy is growing at about a 2.0% pace, although there is considerable month-to-month volatility. Certainly, the labor market is continuing to improve slowly and steadily, and consumer confidence has risen with this better data and declining headline inflation. It is our belief that the economy will maintain this pace of growth in 2012, but we remain concerned about several risks to this outlook. As has been the case for the past two years, macroeconomic concerns — whether they are a hard landing in China, a spike in oil prices, or economic deterioration in Europe — could reassert themselves at any time.

These risk variables have put the Fed in an accommodative stance, which means challenging conditions for money market funds will continue until short-term interest rates begin to rise. When the economic environment starts to solidly improve, we believe interest-rate normalization in the United States will likely occur. Meanwhile, we will continue to focus on safety and liquidity, while looking for competitive yields further out on the money market maturity spectrum when investment opportunities arise.

Thank you, Joanne and Jonathan, for bringing us up to date.

The views expressed in this report are exclusively those of Putnam Management and are subject to change. They are not meant as investment advice.

Please note that the holdings discussed in this report may not have been held by the fund for the entire period. Portfolio composition is subject to review in accordance with the fund’s investment strategy and may vary in the future. Current and future portfolio holdings are subject to risk.

This chart shows how the fund’s top weightings have changed over the past six months. Weightings are shown as a percentage of portfolio value. Summary information may differ from the portfolio schedule included in the financial statements due to the inclusion of derivative securities and the exclusion of as-of trades, if any, and the use of different classifications of securities for presentation purposes. Holdings will vary over time.

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Portfolio Manager Joanne M. Driscoll has an M.B.A. from the Northeastern College of Business Administration and a B.S. from Westfield State College. A CFA charterholder, Joanne joined Putnam in 1995 and has been in the investment industry since 1992.

Portfolio Manager Jonathan M. Topper is a Portfolio Analyst at Putnam. He has a B.A. from Northeastern University. Jonathan has been in the investment industry since he joined Putnam in 1990.

IN THE NEWS

Thirteen years after the 17-member eurozone adopted a single currency, Greece became the first member country to officially default. All three major ratings agencies — Standard & Poor’s, Moody’s Investors Service, and Fitch Ratings — have declared Greece to be in default on its sovereign debt. The majority of private holders of Greek bonds have agreed to exchange their existing bonds for new, longer-dated ones with lower interest rates and substantially lower face values. In addition to the country’s debt restructuring, sellers of credit-default swaps — a form of private insurance against default — have agreed to pay approximately $2.5 billion to settle their contracts. Both the debt restructuring and the credit-default swap settlement were completed without triggering a wave of deleveraging or a liquidity crisis within the European banking sector, thus avoiding the long-feared worst-case scenario for investors. Nonetheless, Europe’s structural imbalances likely will remain with us for some time.

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Your fund’s performance

This section shows your fund’s performance, price, and distribution information for periods ended March 31, 2012, the end of the first half of its current fiscal year. In accordance with regulatory requirements for mutual funds, we also include expense information taken from the fund’s current prospectus. Performance should always be considered in light of a fund’s investment strategy. Data represent past performance. Past performance does not guarantee future results. More recent returns may be less or more than those shown. Investment return and principal value will fluctuate, and you may have a gain or a loss when you sell your shares. Performance information does not reflect any deduction for taxes a shareholder may owe on fund distributions or on the redemption of fund shares. For the most recent month-end performance, please visit the Individual Investors section at putnam.com or call Putnam at 1-800-225-1581. Class R shares are not available to all investors. See the Terms and Definitions section in this report for definitions of the share classes offered by your fund.

Fund performance Total return for periods ended 3/31/12

	Class A	Class B		Class C		Class M	Class R	Class T
(inception dates)	(10/1/76)	(4/27/92)		(2/1/99)		(12/8/94)	(1/21/03)	(12/31/01)
	Net					Net	Net	Net
	asset	Before	After	Before	After	asset	asset	asset
	value	CDSC	CDSC	CDSC	CDSC	value	value	value
Annual average
(life of fund)	5.53%	5.05%	5.05%	5.06%	5.06%	5.39%	5.04%	5.29%
10 years	19.58	15.40	15.40	15.40	15.40	18.29	15.61	17.43
Annual average	1.80	1.44	1.44	1.44	1.44	1.69	1.46	1.62
5 years	6.89	5.76	3.76	5.76	5.76	6.53	5.76	6.30
Annual average	1.34	1.13	0.74	1.13	1.13	1.27	1.13	1.23
3 years	0.16	0.09	–2.91	0.09	0.09	0.12	0.09	0.10
Annual average	0.05	0.03	–0.98	0.03	0.03	0.04	0.03	0.03
1 year	0.01	0.01	–5.00	0.01	–1.00	0.01	0.01	0.01
6 months	0.00	0.00	–5.00	0.00	–1.00	0.00	0.00	0.00
	Net					Net	Net	Net
Current yield	asset	Before	After	Before	After	asset	asset	asset
(end of period)*	value	CDSC	CDSC	CDSC	CDSC	value	value	value
Current 7-day yield
(with expense limitation)	0.01%	0.01%	—	0.01%	—	0.01%	0.01%	0.01%
Current 7-day yield
(without expense limitation)	–0.27	–0.77	—	–0.77	—	–0.42	–0.77	–0.52

Current performance may be lower or higher than the quoted past performance, which cannot guarantee future results. None of the share classes carry an initial sales charge. Class B share returns reflect the applicable contingent deferred sales charge (CDSC), which is 5% in the first year, declining over time to 1% in the sixth year, and is eliminated thereafter. Class C share returns reflect a 1% CDSC for the first year that is eliminated thereafter. Class A, M, R, and T shares generally have no CDSC. Performance for class B, C, M, R, and T shares before their inception is derived from the historical performance of class A shares, adjusted for the applicable sales charge (or CDSC) and the higher operating expenses for such shares.

* The 7-day yield is one of the most common gauges for measuring money market mutual fund performance. Yield reflects current performance more closely than total return.

For a portion of the periods, the fund had expense limitations, without which returns and yields would have been lower.

Class B share performance does not reflect conversion to class A shares.

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Comparative Lipper returns For periods ended 3/31/12

	Lipper Money Market Funds category average*
Annual average (life of fund)	5.65%
10 years	16.40
Annual average	1.53
5 years	5.83
Annual average	1.14
3 years	0.12
Annual average	0.04
1 year	0.02
6 months	0.01

Lipper results should be compared to fund performance at net asset value.

* Over the 6-month, 1-year, 3-year, 5-year, 10-year, and life-of-fund periods ended 3/31/12, there were 259, 258, 244, 232, 185, and 15 funds, respectively, in this Lipper category.

Fund distribution information For the six-month period ended 3/31/12

Distributions	Class A	Class B	Class C	Class M	Class R	Class T
Number	6	6	6	6	6	6
Income	$0.000050	$0.000050	$0.000050	$0.000050	$0.000050	$0.000050
Capital gains	—	—	—	—	—	—
Total	$0.000050	$0.000050	$0.000050	$0.000050	$0.000050	$0.000050

The classification of distributions, if any, is an estimate. Final distribution information will appear on your year-end tax forms.

Your fund’s expenses

As a mutual fund investor, you pay ongoing expenses, such as management fees, distribution fees (12b-1 fees), and other expenses. In the most recent six-month period, your fund’s expenses were limited; had expenses not been limited, they would have been higher. Using the following information, you can estimate how these expenses affect your investment and compare them with the expenses of other funds. You may also pay one-time transaction expenses, including sales charges (loads) and redemption fees, which are not shown in this section and would have resulted in higher total expenses. For more information, see your fund’s prospectus or talk to your financial representative.

Expense ratios

	Class A	Class B	Class C	Class M	Class R	Class T
Total annual operating expenses for the fiscal year
ended 9/30/11	0.50%	1.00%	1.00%	0.65%	1.00%	0.75%
Annualized expense ratio for the six-month period
ended 3/31/12*	0.20%	0.20%	0.20%	0.20%	0.20%	0.20%

Fiscal-year expense information in this table is taken from the most recent prospectus, is subject to change, and may differ from that shown for the annualized expense ratio and in the financial highlights of this report. Expenses are shown as a percentage of average net assets.

* Reflects a voluntary waiver of certain fund expenses.

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Expenses per $1,000

The following table shows the expenses you would have paid on a $1,000 investment in the fund from October 1, 2011, to March 31, 2012. It also shows how much a $1,000 investment would be worth at the close of the period, assuming actual returns and expenses.

	Class A	Class B	Class C	Class M	Class R	Class T
Expenses paid per $1,000*†	$1.00	$1.00	$1.00	$1.00	$1.00	$1.00
Ending value (after expenses)	$1,000.03	$1,000.03	$1,000.03	$1,000.03	$1,000.03	$1,000.03

* Expenses for each share class are calculated using the fund’s annualized expense ratio for each class, which represents the ongoing expenses as a percentage of average net assets for the six months ended 3/31/12. The expense ratio may differ for each share class.

† Expenses are calculated by multiplying the expense ratio by the average account value for the period; then multiplying the result by the number of days in the period; and then dividing that result by the number of days in the year.

Estimate the expenses you paid

To estimate the ongoing expenses you paid for the six months ended March 31, 2012, use the following calculation method. To find the value of your investment on October 1, 2011, call Putnam at 1-800-225-1581.

Compare expenses using the SEC’s method

The Securities and Exchange Commission (SEC) has established guidelines to help investors assess fund expenses. Per these guidelines, the following table shows your fund’s expenses based on a $1,000 investment, assuming a hypothetical 5% annualized return. You can use this information to compare the ongoing expenses (but not transaction expenses or total costs) of investing in the fund with those of other funds. All mutual fund shareholder reports will provide this information to help you make this comparison. Please note that you cannot use this information to estimate your actual ending account balance and expenses paid during the period.

	Class A	Class B	Class C	Class M	Class R	Class T
Expenses paid per $1,000*†	$1.01	$1.01	$1.01	$1.01	$1.01	$1.01
Ending value (after expenses)	$1,024.00	$1,024.00	$1,024.00	$1,024.00	$1,024.00	$1,024.00

* Expenses for each share class are calculated using the fund’s annualized expense ratio for each class, which represents the ongoing expenses as a percentage of average net assets for the six months ended 3/31/12. The expense ratio may differ for each share class.

† Expenses are calculated by multiplying the expense ratio by the average account value for the period; then multiplying the result by the number of days in the period; and then dividing that result by the number of days in the year.

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Terms and definitions

Important terms

Total return shows how the value of the fund’s shares changed over time, assuming you held the shares through the entire period and reinvested all distributions in the fund.

Net asset value (NAV) is the price, or value, of one share of a mutual fund, without a sales charge. Net asset values fluctuate with market conditions, and are calculated by dividing the net assets of each class of shares by the number of outstanding shares in the class.

Contingent deferred sales charge (CDSC) is generally a charge applied at the time of the redemption of class B or C shares and assumes redemption at the end of the period. Your fund’s class B CDSC declines over time from a 5% maximum during the first year to 1% during the sixth year. After the sixth year, the CDSC no longer applies. The CDSC for class C shares is 1% for one year after purchase.

Current yield is the annual rate of return earned from dividends or interest of an investment. Current yield is expressed as a percentage of the price of a security, fund share, or principal investment.

Share classes

Class A shares generally are fund shares purchased with an initial sales charge. In the case of your fund, which has no sales charge, the reference is to shares purchased or acquired through the exchange of class A shares from another Putnam fund. Exchange of your fund’s class A shares into another fund may involve a sales charge, however.

Class B shares are not subject to an initial sales charge. They may be subject to a CDSC.

Class C shares are not subject to an initial sales charge and are subject to a CDSC only if the shares are redeemed during the first year.

Class M shares generally are fund shares that have a lower initial sales charge and a higher 12b-1 fee than class A shares and no CDSC. In the case of your fund, which has no sales charge, the reference is to shares purchased or acquired through the exchange of class M shares from another Putnam fund. Exchange of your fund’s class M shares into another fund may involve a sales charge, however.

Class R shares are not subject to an initial sales charge or CDSC and are available only to certain defined contribution plans.

Class T shares are not subject to an initial sales charge or a CDSC (except on certain redemptions of shares acquired by exchange of shares of another Putnam fund bought without an initial sales charge); however, they are subject to a 12b-1 fee.

Comparative indexes

Barclays Capital U.S. Aggregate Bond Index is an unmanaged index of U.S. investment-grade fixed-income securities.

BofA (Bank of America) Merrill Lynch U.S. 3-Month Treasury Bill Index is an unmanaged index that seeks to measure the performance of U.S. Treasury bills available in the marketplace.

Lipper Money Market Funds category average is an arithmetic average of the total return of all money market mutual funds tracked by Lipper.

S&P 500 Index is an unmanaged index of common stock performance.

Indexes assume reinvestment of all distributions and do not account for fees. Securities and performance of a fund and an index will differ. You cannot invest directly in an index.

Lipper is a third-party industry-ranking entity that ranks mutual funds. Its rankings do not reflect sales charges. Lipper rankings are based on total return at net asset value relative to other funds that have similar current investment styles or objectives as determined by Lipper. Lipper may change a fund’s category assignment at its discretion. Lipper category averages reflect performance trends for funds within a category.

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Other information for shareholders

Important notice regarding delivery of shareholder documents

In accordance with Securities and Exchange Commission (SEC) regulations, Putnam sends a single copy of annual and semiannual shareholder reports, prospectuses, and proxy statements to Putnam shareholders who share the same address, unless a shareholder requests otherwise. If you prefer to receive your own copy of these documents, please call Putnam at 1-800-225-1581, and Putnam will begin sending individual copies within 30 days.

Proxy voting

Putnam is committed to managing our mutual funds in the best interests of our shareholders. The Putnam funds’ proxy voting guidelines and procedures, as well as information regarding how your fund voted proxies relating to portfolio securities during the 12-month period ended June 30, 2011, are available in the Individual Investors section of putnam.com, and on the SEC’s website, www.sec.gov. If you have questions about finding forms on the SEC’s website, you may call the SEC at 1-800-SEC-0330. You may also obtain the Putnam funds’ proxy voting guidelines and procedures at no charge by calling Putnam’s Shareholder Services at 1-800-225-1581.

Fund portfolio holdings

The fund will file a complete schedule of its portfolio holdings with the SEC for the first and third quarters of each fiscal year on Form N-Q. Shareholders may obtain the fund’s Forms N-Q on the SEC’s website at www.sec.gov. In addition, the fund’s Forms N-Q may be reviewed and copied at the SEC’s Public Reference Room in Washington, D.C. You may call the SEC at 1-800-SEC-0330 for information about the SEC’s website or the operation of the Public Reference Room.

Trustee and employee fund ownership

Putnam employees and members of the Board of Trustees place their faith, confidence, and, most importantly, investment dollars in Putnam mutual funds. As of March 31, 2012, Putnam employees had approximately $353,000,000 and the Trustees had approximately $81,000,000 invested in Putnam mutual funds. These amounts include investments by the Trustees’ and employees’ immediate family members as well as investments through retirement and deferred compensation plans.

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Financial statements

A guide to financial statements

These sections of the report, as well as the accompanying Notes, constitute the fund’s financial statements.

The fund’s portfolio lists all the fund’s investments and their values as of the last day of the reporting period. Holdings are organized by asset type and industry sector, country, or state to show areas of concentration and diversification.

Statement of assets and liabilities shows how the fund’s net assets and share price are determined. All investment and non-investment assets are added together. Any unpaid expenses and other liabilities are subtracted from this total. The result is divided by the number of shares to determine the net asset value per share, which is calculated separately for each class of shares. (For funds with preferred shares, the amount subtracted from total assets includes the liquidation preference of preferred shares.)

Statement of operations shows the fund’s net investment gain or loss. This is done by first adding up all the fund’s earnings — from dividends and interest income — and subtracting its operating expenses to determine net investment income (or loss). Then, any net gain or loss the fund realized on the sales of its holdings — as well as any unrealized gains or losses over the period — is added to or subtracted from the net investment result to determine the fund’s net gain or loss for the fiscal period.

Statement of changes in net assets shows how the fund’s net assets were affected by the fund’s net investment gain or loss, by distributions to shareholders, and by changes in the number of the fund’s shares. It lists distributions and their sources (net investment income or realized capital gains) over the current reporting period and the most recent fiscal year-end. The distributions listed here may not match the sources listed in the Statement of operations because the distributions are determined on a tax basis and may be paid in a different period from the one in which they were earned. Dividend sources are estimated at the time of declaration. Actual results may vary. Any non-taxable return of capital cannot be determined until final tax calculations are completed after the end of the fund’s fiscal year.

Financial highlights provide an overview of the fund’s investment results, per-share distributions, expense ratios, net investment income ratios, and portfolio turnover in one summary table, reflecting the five most recent reporting periods. In a semiannual report, the highlights table also includes the current reporting period.

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The fund’s portfolio 3/31/12 (Unaudited)

REPURCHASE AGREEMENTS (25.7%)*	Principal amount	Value
Interest in $336,173,000 joint tri-party repurchase agreement dated
3/30/12 with Citigroup Global Markets, Inc. due 4/2/12 — maturity
value of $74,000,925 for an effective yield of 0.15% (collateralized by
various mortgage-backed securities with coupon rates ranging from
zero % to 5.50% and due dates ranging from 7/1/19 to 3/1/42,
valued at $342,896,460)	$74,000,000	$74,000,000
Interest in $83,000,000 joint tri-party repurchase agreement dated
3/30/12 with Deutsche Bank Securities, Inc. due 4/2/12 — maturity
value of $74,000,925 for an effective yield of 0.15% (collateralized by
a mortgage-backed security with a coupon rate of 4.50% and a due
date of 5/1/41, valued at $84,660,001)	74,000,000	74,000,000
Interest in $287,000,000 joint tri-party repurchase agreement dated
3/30/12 with Goldman Sach & Co. due 4/2/12 — maturity value
of $74,000,925 for an effective yield of 0.15% (collateralized by various
mortgage-backed securities with coupon rates ranging from 2.50%
to 4.50% and due dates ranging from 3/1/27 to 11/1/41, valued
at $292,740,000)	74,000,000	74,000,000
Interest in $82,300,000 joint tri-party repurchase agreement dated
3/30/12 with JPMorgan Securities, Inc. due 4/2/12 — maturity value
of $33,750,563 for an effective yield of 0.20% (collateralized by various
corporate bonds and notes with coupon rates ranging from 2.95%
to 9.375% and due dates ranging from 2/1/14 to 9/30/39, valued
at $86,420,263)	33,750,000	33,750,000
Interest in $375,000,000 joint tri-party repurchase agreement dated
3/30/12 with JPMorgan Securities, Inc. due 4/2/12 — maturity value
of $73,856,862 for an effective yield of 0.14% (collateralized by various
mortgage-backed securities with coupon rates ranging from 2.50%
to 7.50% and due dates ranging from 1/1/13 to 4/1/42, valued
at $382,500,252)	73,856,000	73,856,000
Interest in $300,800,000 joint tri-party term repurchase agreement
dated 3/27/12 with Citigroup Global Markets, Inc. due 4/3/12, 0.18%
(collateralized by various mortgage-backed securities with coupon
rates ranging from 3.30% to 4.50% and due dates ranging from 12/1/20
to 3/1/42, valued at $306,816,796) TR	34,000,000	34,000,000
Interest in $160,000,000 joint tri-party term repurchase agreement
dated 3/28/12 with Deutsche Bank Securities, Inc. due 4/4/12, 0.14%
(collateralized by various mortgage-backed securities with coupon
rates ranging from 3.50% to 4.50% and due dates ranging from 12/1/26
to 11/1/41, valued at $163,454,988) TR	17,500,000	17,500,000
Interest in $48,750,000 joint tri-party term repurchase agreement
dated 3/23/12 with JPMorgan Securities, Inc. due 4/23/12, 0.27%
(collateralized by various corporate bonds and notes with coupon
rates ranging from 5.75% to 8.25% and due dates ranging from 4/15/12
to 10/15/39, valued at $51,190,659) TR	13,350,000	13,350,000
Interest in $34,000,000 tri-party term repurchase agreement dated
3/27/12 with Barclays Capital, Inc. due 4/3/12, 0.15% (collateralized
by various mortgage-backed securities with coupon rates ranging
from 2.50% to 4.50% and due dates ranging from 3/1/22 to 1/1/42,
valued at $34,680,001) TR	34,000,000	34,000,000
Total repurchase agreements (cost $428,456,000)		$428,456,000

16

ASSET-BACKED COMMERCIAL PAPER (17.3%)*	Yield (%)	Maturity date	Principal amount	Value
Alpine Securitization Corp. (Switzerland)	0.180	4/18/12	$8,400,000	$8,399,286
Bryant Park Funding, LLC	0.270	6/15/12	15,000,000	14,991,563
Bryant Park Funding, LLC	0.240	6/27/12	1,770,000	1,768,973
CAFCO, LLC	0.300	4/9/12	5,700,000	5,699,620
CAFCO, LLC	0.220	4/11/12	2,700,000	2,699,835
Chariot Funding, LLC	0.190	5/29/12	8,561,000	8,558,379
Chariot Funding, LLC	0.190	5/16/12	8,000,000	7,998,100
CHARTA, LLC	0.280	4/2/12	8,400,000	8,399,935
CIESCO-LP	0.270	4/4/12	8,400,000	8,399,811
CRC Funding, LLC	0.220	4/10/12	8,400,000	8,399,538
Fairway Finance, LLC (Canada)	0.160	6/5/12	7,660,000	7,657,787
Fairway Finance, LLC 144A (Canada)	0.282	8/16/12	12,000,000	12,000,000
Fairway Finance, LLC 144A (Canada)	0.250	6/4/12	5,500,000	5,497,556
Govco, LLC	0.270	4/2/12	8,400,000	8,399,937
Jupiter Securitization Co., LLC	0.190	6/7/12	10,800,000	10,796,181
Jupiter Securitization Co., LLC	0.190	5/8/12	6,000,000	5,998,828
Liberty Street Funding, LLC (Canada)	0.210	4/17/12	7,800,000	7,799,272
Manhattan Asset Funding Co., LLC (Japan)	0.280	5/16/12	2,100,000	2,099,265
Manhattan Asset Funding Co., LLC (Japan)	0.260	4/16/12	3,100,000	3,099,664
Manhattan Asset Funding Co., LLC (Japan)	0.230	4/18/12	6,300,000	6,299,316
Old Line Funding, LLC	0.240	6/22/12	8,500,000	8,495,353
Old Line Funding, LLC	0.200	5/15/12	14,000,000	13,996,578
Old Line Funding, LLC 144A	0.200	4/16/12	3,000,000	2,999,750
Straight-A Funding, LLC	0.180	5/14/12	5,000,000	4,998,925
Straight-A Funding, LLC	0.180	5/1/12	17,000,000	16,997,450
Straight-A Funding, LLC 144A, Ser. 1	0.190	4/17/12	9,000,000	8,999,240
Straight-A Funding, LLC 144A, Ser. 1	0.180	6/15/12	18,000,000	17,993,250
Straight-A Funding, LLC 144A, Ser. 1	0.180	5/17/12	1,400,000	1,399,678
Thunder Bay Funding, LLC	0.210	5/1/12	8,800,000	8,798,460
Variable Funding Capital Co., LLC 144A
(Wachovia Bank NA (LOC))	0.180	4/26/12	10,700,000	10,698,663
Variable Funding Capital Co., LLC 144A
(Wachovia Bank NA (LOC))	0.170	4/27/12	15,250,000	15,248,128
Victory Receivables Corp. (Japan)	0.290	5/7/12	15,500,000	15,495,505
Victory Receivables Corp. (Japan)	0.280	6/15/12	10,000,000	9,994,167
Working Capital Management Co. (Japan)	0.230	4/3/12	8,434,000	8,433,892
Total asset-backed commercial paper (cost $289,511,885)				$289,511,885
COMMERCIAL PAPER (14.2%)*	Yield (%)	Maturity date	Principal amount	Value
Australia & New Zealand Banking Group, Ltd.
(Australia)	0.541	6/29/12	$5,500,000	$5,492,658
Australia & New Zealand Banking Group, Ltd.
(Australia)	0.351	8/8/12	9,800,000	9,787,709
Australia & New Zealand Banking Group, Ltd.
144A (Australia)	0.648	1/10/13	10,400,000	10,400,000
Axis Bank, Ltd. (India)	0.500	4/12/12	8,400,000	8,398,717
COFCO Capital Corp.	0.405	4/3/12	17,000,000	16,999,617

17

COMMERCIAL PAPER (14.2%)* cont.	Yield (%)	Maturity date	Principal amount	Value
Commonwealth Bank of Australia 144A
(Australia)	0.190	6/8/12	$14,000,000	$14,000,000
Commonwealth Bank of Australia 144A
(Australia)	0.180	10/18/12	3,100,000	3,099,944
Danske Corp. (Denmark)	0.210	4/4/12��	8,400,000	8,399,853
DnB Bank ASA (Norway)	0.411	6/29/12	14,500,000	14,485,303
DnB Bank ASA 144A (Norway)	0.422	4/25/12	10,600,000	10,600,000
General Electric Capital Corp.	0.190	5/23/12	9,000,000	8,997,530
General Electric Capital Services	0.120	4/30/12	3,100,000	3,099,700
HSBC Bank USA, NA	0.300	7/26/12	7,000,000	6,993,233
HSBC USA, Inc. (United Kingdom)	0.290	6/26/12	9,500,000	9,493,419
ING (US) Funding, LLC	0.180	4/9/12	8,400,000	8,399,664
Louis Dreyfus Commodities, LLC, Ser. BARC
(Barclays Bank PLC (LOC))	0.500	4/5/12	8,400,000	8,399,533
Nordea North America Inc./DE (Sweden)	0.542	9/7/12	8,950,000	8,928,654
Standard Chartered Bank/New York	0.531	8/20/12	8,000,000	7,983,393
Standard Chartered Bank/New York	0.501	7/9/12	7,900,000	7,889,138
State Street Corp.	0.240	7/5/12	10,000,000	9,993,667
State Street Corp.	0.230	7/19/12	7,000,000	6,995,125
Sumitomo Mitsui Banking Corp. (Japan)	0.300	4/18/12	4,670,000	4,669,338
Toyota Credit Canada, Inc. (Canada)	0.180	5/29/12	8,450,000	8,447,550
Toyota Motor Credit Corp.	0.160	5/15/12	8,000,000	7,998,436
Westpac Banking Corp. 144A (Australia)	0.744	8/24/12	9,300,000	9,272,281
Westpac Banking Corp. 144A (Australia)	0.230	7/5/12	18,000,000	18,000,000
Total commercial paper (cost $237,224,462)				$237,224,462

MUNICIPAL BONDS		Maturity		Principal
AND NOTES (12.7%)*	Yield (%)	date	Rating**	amount	Value
California (1.5%)
Board of Trustees of the Leland Stanford
Junior University Commercial Paper	0.130	4/5/12	P-1	$18,200,000	$18,199,737
California Educational Facilities Authority
Commercial Paper (Stanford University),
Ser. STAN	0.120	4/20/12	P-1	7,000,000	7,000,000
					25,199,737
Connecticut (1.6%)
Yale University Commercial Paper	0.120	4/2/12	P-1	26,300,000	26,299,912
					26,299,912
District of Columbia (0.2%)
American University Commercial Paper,
Ser. A	0.200	6/19/12	A-1	3,500,000	3,498,464
					3,498,464
Florida (0.7%)
Highlands County, Health Facilities
Authority VRDN (Adventist Health),
Ser. H (U.S. Bank, N.A. (LOC)) M	0.160	11/15/35	VMIG1	11,750,000	11,750,000
					11,750,000

18

MUNICIPAL BONDS		Maturity		Principal
AND NOTES (12.7%)* cont.	Yield (%)	date	Rating**	amount	Value
Indiana (1.2%)
Saint Joseph County Commercial Paper
(University of Notre Dame Du Lac)	0.150	5/3/12	P-1	$12,000,000	$11,998,400
Saint Joseph County Commercial Paper
(University of Notre Dame Du Lac)	0.140	4/4/12	P-1	7,276,000	7,275,915
					19,274,315
Kentucky (1.1%)
Catholic Health Initiatives Commercial
Paper, Ser. A	0.120	4/2/12	P-1	6,870,000	6,870,000
Kentucky State Economic Development
Finance Authority VRDN (Catholic Health
Initiatives), Ser. C M	0.180	5/1/34	VMIG1	11,000,000	11,000,000
					17,870,000
Maryland (1.2%)
Johns Hopkins University Commercial
Paper, Ser. A	0.160	5/15/12	P-1	3,250,000	3,250,000
Johns Hopkins University Commercial
Paper, Ser. A	0.150	6/21/12	P-1	12,367,000	12,367,000
Johns Hopkins University Commercial
Paper, Ser. C	0.180	6/11/12	P-1	5,000,000	5,000,000
					20,617,000
Massachusetts (1.1%)
Harvard University Commercial Paper	0.130	5/15/12	P-1	18,802,000	18,799,013
					18,799,013
Michigan (0.5%)
Trinity Health Corporation Commercial
Paper	0.150	4/2/12	P-1	8,200,000	8,199,966
					8,199,966
Nevada (0.4%)
Truckee Meadows, Water Authority
Revenue Commercial Paper,
Ser. 06-B (Lloyds TSB Bank PLC/
New York, NY (LOC))	0.180	4/11/12	P-1	7,000,000	7,000,000
					7,000,000
North Carolina (1.0%)
Duke University Commercial Paper,
Ser. B-98	0.180	6/19/12	P-1	15,810,000	15,803,755
Wake County VRDN, Ser. B M	0.170	3/1/24	VMIG1	1,500,000	1,500,000
					17,303,755
Texas (1.9%)
Harris County, Health Facilities
Development Authority VRDN (Texas
Childrens Hospital), Ser. B-1 M	0.200	10/1/29	VMIG1	3,795,000	3,795,000
University of Texas Permanent University
Fund Commercial Paper	0.120	4/2/12	P-1	28,000,000	28,000,000
					31,795,000
Wisconsin (0.3%)
Wisconsin State Health & Educational
Facilities Authority VRDN (Wheaton
Franciscan Services), Ser. B
(U.S. Bank, N.A. (LOC)) M	0.190	8/15/33	VMIG1	4,100,000	4,100,000
					4,100,000
Total municipal bonds and notes (cost $211,707,162)					$211,707,162

19

U.S. TREASURY OBLIGATIONS (10.0%)*	Yield (%)	Maturity date	Principal amount	Value
U.S. Treasury Bills	0.151	10/18/12	$20,000,000	$19,983,056
U.S. Treasury Bills	0.138	10/18/12	15,000,000	14,988,333
U.S. Treasury Bills	0.099	7/19/12	15,000,000	14,995,458
U.S. Treasury Bills	0.099	7/12/12	20,000,000	19,994,333
U.S. Treasury Notes k	1.500	7/15/12	25,000,000	25,101,111
U.S. Treasury Notes k	1.375	10/15/12	33,300,000	33,517,115
U.S. Treasury Notes k	0.625	1/31/13	18,000,000	18,063,909
U.S. Treasury Notes k	0.625	7/31/12	19,500,000	19,533,855
Total U.S. treasury obligations (cost $166,177,170)				$166,177,170
U.S. GOVERNMENT AGENCY OBLIGATIONS (8.9%)*	Yield (%)	Maturity date	Principal amount	Value
Federal Farm Credit Bank FRB, Ser. 1	0.230	1/14/13	$24,300,000	$24,300,000
Federal Home Loan Bank unsec. discount notes	0.115	8/3/12	6,500,000	6,497,425
Federal Home Loan Bank unsec. discount notes	0.080	6/1/12	3,590,000	3,589,513
Federal Home Loan Bank unsec. discount notes	0.070	5/30/12	5,000,000	4,999,426
Federal Home Loan Mortgage Corp. unsec.
discount notes	0.085	6/25/12	8,300,000	8,298,334
Federal Home Loan Mortgage Corp. unsec.
discount notes	0.075	5/21/12	1,100,000	1,099,885
Federal Home Loan Mortgage Corp. unsec.
discount notes, Ser. RB	0.170	10/23/12	20,000,000	19,980,639
Federal National Mortgage Association unsec.
discount notes	0.140	8/15/12	25,000,000	24,986,778
Federal National Mortgage Association unsec.
discount notes	0.110	6/25/12	3,300,000	3,299,143
Federal National Mortgage Association unsec.
discount notes	0.080	5/16/12	13,350,000	13,348,665
Federal National Mortgage Association unsec.
discount notes	0.065	5/9/12	13,000,000	12,999,108
General Electric Capital Corp. FDIC guaranteed
notes, MTN, Ser. G k	2.200	6/8/12	25,188,000	25,285,990
Total U.S. government agency obligations (cost $148,684,906)				$148,684,906
CORPORATE BONDS AND NOTES (6.4%)*	Interest	Maturity	Principal
	rate (%)	date	amount	Value
Commonwealth Bank of Australia 144A
sr. unsec. notes FRN (Australia)	1.024	3/19/13	$7,850,000	$7,885,231
General Electric Capital Corp. sr. unsec.
notes FRN, EMTN	0.579	5/29/12	2,900,000	2,901,028
HSBC Bank PLC 144A sr. unsec. unsub. notes
FRN (United Kingdom)	0.965	1/18/13	8,650,000	8,667,939
JPMorgan Chase & Co. sr. unsec. unsub. notes
FRN, MTN	1.141	2/26/13	7,000,000	7,041,760
National Australia Bank, Ltd. 144A sr. unsec.
unsub. notes (Australia)	2.350	11/16/12	15,275,000	15,440,934
Royal Bank of Canada 144A sr. unsec. notes
FRN (Canada) M	0.702	5/15/14	29,425,000	29,427,879
Svenska Handelsbanken AB 144A sr. unsec.
unsub. notes FRN (Sweden)	1.474	9/14/12	2,000,000	2,008,217

20

CORPORATE BONDS AND NOTES (6.4%)* cont.	Interest	Maturity	Principal
	rate (%)	date	amount	Value
Svenska Handelsbanken/New York, NY
144A notes FRN (Sweden)	0.515	1/7/13	$23,500,000	$23,500,000
Wal-Mart Stores, Inc. sr. unsec. unsub
notes stepped-coupon (zero %, 6/1/12) †† M	5.226	6/1/18	10,500,000	10,589,218
Total corporate bonds and notes (cost $107,462,206)				$107,462,206
CERTIFICATES OF DEPOSIT (5.4%)*	Interest	Maturity	Principal
	rate (%)	date	amount	Value
Bank of Nova Scotia/Houston	0.560	6/21/12	$10,500,000	$10,500,000
Bank of Nova Scotia/Houston FRN	0.322	7/26/12	9,000,000	9,000,000
Canadian Imperial Bank of Commerce/
New York, NY FRN (Canada)	0.432	10/15/12	8,500,000	8,500,000
National Australia Bank, Ltd. (Australia)	0.490	4/11/12	10,000,000	10,000,028
Nordea Bank Finland PLC/New York	0.874	9/13/12	17,150,000	17,142,420
Standard Chartered Bank/New York	0.675	9/10/12	9,200,000	9,200,000
Toronto-Dominion Bank/NY (Canada)	0.582	10/19/12	14,500,000	14,500,000
Toronto-Dominion Bank/NY (Canada)	0.210	5/8/12	3,000,000	3,000,062
Toronto-Dominion Bank/NY FRN (Canada)	0.312	9/20/12	8,370,000	8,370,875
Total certificates of deposit (cost $90,213,385)				$90,213,385
TOTAL INVESTMENTS
Total investments (cost $1,679,437,176)				$1,679,437,176

Key to holding’s abbreviations

EMTN	Euro Medium Term Notes
FDIC Guaranteed	Federal Deposit Insurance Corp. Guaranteed
FRB	Floating Rate Bonds: the rate shown is the current interest rate at the close of the reporting period
FRN	Floating Rate Notes: the rate shown is the current interest rate at the close of the reporting period
LOC	Letter of Credit
MTN	Medium Term Notes
VRDN	Variable Rate Demand Notes, which are floating-rate securities with long-term maturities, that
	carry coupons that reset every one or seven days. The rate shown is the current interest rate at
	the close of the reporting period.

Notes to the fund’s portfolio

Unless noted otherwise, the notes to the fund’s portfolio are for the close of the fund’s reporting period, which ran from October 1, 2011 through March 31, 2012 (the reporting period). Within the following notes to the portfolio, references to “ASC 820” represent Accounting Standards Codification ASC 820 Fair Value Measurements and Disclosures.

* Percentages indicated are based on net assets of $1,669,361,079.

** The Moody’s, Standard & Poor’s or Fitch ratings indicated are believed to be the most recent ratings available at the close of the reporting period for the securities listed. Ratings are generally ascribed to securities at the time of issuance. While the agencies may from time to time revise such ratings, they undertake no obligation to do so, and the ratings do not necessarily represent what the agencies would ascribe to these securities at the close of the reporting period. The rating of an insured security represents what is believed to be the most recent rating of the insurer’s claims-paying ability available at the close of the reporting period and does not reflect any subsequent changes. Security ratings are defined in the Statement of Additional Information.

†† The interest rate and date shown parenthetically represent the new interest rate to be paid and the date the fund will begin accruing interest at this rate.

^k The rates shown are the current interest rates at the close of the reporting period.

21

^M The security’s effective maturity date is less than one year.

^TR Maturity value of a term repurchase agreement will equal the principal amount of the repurchase agreement plus interest.

Debt obligations are considered secured unless otherwise indicated.

144A after the name of an issuer represents securities exempt from registration under Rule 144A under the Securities Act of 1933, as amended. These securities may be resold in transactions exempt from registration, normally to qualified institutional buyers.

The dates shown on debt obligations are the original maturity dates.

DIVERSIFICATION BY COUNTRY
Distribution of investments by country of risk at the close of the reporting period, excluding collateral received, if any (as a percentage of Portfolio Value):
United States	78.5%	United Kingdom	1.1%
Canada	6.3	Denmark	0.5
Australia	6.1	Switzerland	0.5
Japan	3.0	India	0.5
Sweden	2.0	Total	100.0%
Norway	1.5

ASC 820 establishes a three-level hierarchy for disclosure of fair value measurements. The valuation hierarchy is based upon the transparency of inputs to the valuation of the fund’s investments. The three levels are defined as follows:

Level 1: Valuations based on quoted prices for identical securities in active markets.

Level 2: Valuations based on quoted prices in markets that are not active or for which all significant inputs are observable, either directly or indirectly.

Level 3: Valuations based on inputs that are unobservable and significant to the fair value measurement.

The following is a summary of the inputs used to value the fund’s net assets as of the close of the reporting period:

		Valuation inputs
Investments in securities:	Level 1	Level 2	Level 3
Asset-backed commercial paper	$—	$289,511,885	$—
Certificates of deposit	—	90,213,385	—
Commercial paper	—	237,224,462	—
Corporate bonds and notes	—	107,462,206	—
Municipal bonds and notes	—	211,707,162	—
Repurchase agreements	—	428,456,000	—
U.S. government agency obligations	—	148,684,906	—
U.S. treasury obligations	—	166,177,170	—
Totals by level	$—	$1,679,437,176	$—

The accompanying notes are an integral part of these financial statements.

22

Statement of assets and liabilities 3/31/12 (Unaudited)

ASSETS
Investment in securities, at value (Note 1):
Unaffiliated issuers (at amortized cost)	$1,250,981,176
Repurchase agreements (identified cost $428,456,000)	428,456,000
Cash	1,916
Interest and other receivables	1,508,550
Receivable for shares of the fund sold	4,346,304
Total assets	1,685,293,946
LIABILITIES
Distributions payable to shareholders	6,293
Payable for investments purchased	2,902,405
Payable for shares of the fund repurchased	12,113,885
Payable for compensation of Manager (Note 2)	57,770
Payable for investor servicing fees (Note 2)	233,763
Payable for custodian fees (Note 2)	20,559
Payable for Trustee compensation and expenses (Note 2)	408,600
Payable for administrative services (Note 2)	7,000
Other accrued expenses	182,592
Total liabilities	15,932,867
Net assets	$1,669,361,079
REPRESENTED BY
Paid-in capital (Unlimited shares authorized) (Notes 1 and 4)	$1,670,671,882
Undistributed net investment income (Note 1)	81
Accumulated net realized loss on investments (Note 1)	(1,310,884)
Total — Representing net assets applicable to capital shares outstanding	$1,669,361,079
COMPUTATION OF NET ASSET VALUE AND OFFERING PRICE
Net asset value, offering price and redemption price per class A share
($1,543,588,915 divided by 1,546,452,358 shares)	$1.00
Net asset value and offering price per class B share ($21,298,600 divided by 21,339,460 shares)*	$1.00
Net asset value and offering price per class C share ($27,044,641 divided by 27,094,133 shares)*	$1.00
Net asset value, offering price and redemption price per class M share
($27,714,001 divided by 27,765,479 shares)	$1.00
Net asset value, offering price and redemption price per class R share
($19,848,257 divided by 19,881,526 shares)	$1.00
Net asset value, offering price and redemption price per class T share
($29,866,665 divided by 29,918,256 shares)	$1.00

* Redemption price per share is equal to net asset value less any applicable contingent deferred sales charge.

The accompanying notes are an integral part of these financial statements.

23

Statement of operations Six months ended 3/31/12 (Unaudited)

INVESTMENT INCOME
Interest (including interest income of $14,112 from investments in affiliated issuers) (Note 5)	$1,888,252
EXPENSES
Compensation of Manager (Note 2)	2,622,836
Investor servicing fees (Note 2)	1,503,727
Custodian fees (Note 2)	18,929
Trustee compensation and expenses (Note 2)	80,538
Administrative services (Note 2)	23,099
Distribution fees — Class B (Note 2)	60,449
Distribution fees — Class C (Note 2)	72,571
Distribution fees — Class M (Note 2)	22,195
Distribution fees — Class R (Note 2)	47,408
Distribution fees — Class T (Note 2)	39,464
Other	334,159
Fees waived and reimbursed by Manager (Note 2)	(3,020,303)
Total expenses	1,805,072
Expense reduction (Note 2)	(7,663)
Net expenses	1,797,409
Net investment income	90,843
Net realized gain on investments (Notes 1 and 3)	70,745
Net gain on investments	70,745
Net increase in net assets resulting from operations	$161,588

The accompanying notes are an integral part of these financial statements.

24

Statement of changes in net assets

DECREASE IN NET ASSETS	Six months ended 3/31/12*	Year ended 9/30/11
Operations:
Net investment income	$90,843	$244,962
Net realized gain on investments	70,745	224,432
Net increase in net assets resulting from operations	161,588	469,394
Distributions to shareholders (Note 1):
From ordinary income
Net investment income
Class A	(82,478)	(246,692)
Class B	(1,208)	(4,169)
Class C	(1,454)	(3,340)
Class M	(1,482)	(4,478)
Class R	(950)	(2,342)
Class T	(1,581)	(4,633)
Decrease from capital share transactions (Note 4)	(212,656,531)	(392,018,220)
Total decrease in net assets	(212,584,096)	(391,814,480)
NET ASSETS
Beginning of period	1,881,945,175	2,273,759,655
End of period (including undistributed net investment
income of $81 and distributions in excess of net investment
income of $1,609, respectively)	$1,669,361,079	$1,881,945,175

* Unaudited

The accompanying notes are an integral part of these financial statements.

25

Financial highlights (For a common share outstanding throughout the period)

INVESTMENT OPERATIONS:					LESS DISTRIBUTIONS:					RATIOS AND SUPPLEMENTAL DATA:
												Ratio of net
												investment
												income
	Net asset										Ratio	(loss)
	value,		Net realized	Total from	From				Total return	Net assets,	of expenses	to average
	beginning	Net investment	gain (loss)	investment	net investment	From	Total	Net asset value,	at net asset	end of period	to average	net assets
Period ended	of period	income (loss)	on investments	operations	income	return of capital	distributions	end of period	value (%) a	(in thousands)	net assets (%) b	(%)
Class A
March 31, 2012 **	$1.00	.0001	— c	.0001	(.0001)	—	(.0001)	$1.00	— *d	$1,543,589	.10 *e	.01 *e
September 30, 2011	1.00	.0001	.0001	.0002	(.0001)	—	(.0001)	1.00	.01	1,739,458	.22 e	.01 e
September 30, 2010	1.00	.0001	(.0003)	(.0002)	(.0005)	—	(.0005)	1.00	.06	2,131,331	.32 e	— e,f
September 30, 2009	1.00	.0091	(.0001)	.0090	(.0086)	—	(.0086)	1.00	.86	2,482,270	.56 e,g	.98 e,g
September 30, 2008	1.00	.0327	(.0002)	.0325	(.0325)	(.0004)	(.0329)	1.00	3.35	3,212,674	.56 g	3.28 g
September 30, 2007	1.00	.0486 h	— c	.0486	(.0489)	—	(.0489)	1.00	5.01	3,394,996	.54 g	4.84 g,h
Class B
March 31, 2012 **	$1.00	.0001	— c	.0001	(.0001)	—	(.0001)	$1.00	— *d	$21,299	.10 *e	.01 *e
September 30, 2011	1.00	.0001	.0001	.0002	(.0001)	—	(.0001)	1.00	.01	27,668	.22 e	.01 e
September 30, 2010	1.00	.0001	(.0003)	(.0002)	(.0005)	—	(.0005)	1.00	.06	37,121	.32 e	.01 e
September 30, 2009	1.00	.0060	(.0001)	.0059	(.0054)	—	(.0054)	1.00	.54	66,020	.91 e,g	.68 e,g
September 30, 2008	1.00	.0277	(.0002)	.0275	(.0276)	(.0003)	(.0279)	1.00	2.83	99,244	1.06 g	2.83 g
September 30, 2007	1.00	.0436 h	— c	.0436	(.0439)	—	(.0439)	1.00	4.49	117,474	1.04 g	4.34 g,h
Class C
March 31, 2012 **	$1.00	.0001	— c	.0001	(.0001)	—	(.0001)	$1.00	— *d	$27,045	.10 *e	.01 *e
September 30, 2011	1.00	.0001	.0001	.0002	(.0001)	—	(.0001)	1.00	.01	31,073	.22 e	.01 e
September 30, 2010	1.00	.0001	(.0003)	(.0002)	(.0005)	—	(.0005)	1.00	.06	21,991	.32 e	— e,f
September 30, 2009	1.00	.0060	(.0001)	.0059	(.0054)	—	(.0054)	1.00	.54	27,757	.89 e,g	.62 e,g
September 30, 2008	1.00	.0277	(.0002)	.0275	(.0276)	(.0003)	(.0279)	1.00	2.83	30,609	1.06 g	2.66 g
September 30, 2007	1.00	.0436 h	— c	.0436	(.0439)	—	(.0439)	1.00	4.49	19,456	1.04 g	4.34 g,h
Class M
March 31, 2012 **	$1.00	.0001	— c	.0001	(.0001)	—	(.0001)	$1.00	— *d	$27,714	.10 *e	.01 *e
September 30, 2011	1.00	.0001	.0001	.0002	(.0001)	—	(.0001)	1.00	.01	31,296	.22 e	.01 e
September 30, 2010	1.00	.0001	(.0003)	(.0002)	(.0005)	—	(.0005)	1.00	.06	35,999	.32 e	— e,f
September 30, 2009	1.00	.0080	(.0001)	.0079	(.0074)	—	(.0074)	1.00	.74	46,293	.68 e,g	.83 e,g
September 30, 2008	1.00	.0312	(.0002)	.0310	(.0310)	(.0004)	(.0314)	1.00	3.19	53,452	.71 g	3.07 g
September 30, 2007	1.00	.0471 h	— c	.0471	(.0474)	—	(.0474)	1.00	4.86	42,641	.69 g	4.69 g,h
Class R
March 31, 2012 **	$1.00	.0001	— c	.0001	(.0001)	—	(.0001)	$1.00	— *d	$19,848	.10 *e	.01 *e
September 30, 2011	1.00	.0001	.0001	.0002	(.0001)	—	(.0001)	1.00	.01	18,508	.22 e	.01 e
September 30, 2010	1.00	.0001	(.0003)	(.0002)	(.0005)	—	(.0005)	1.00	.06	16,283	.32 e	— e,f
September 30, 2009	1.00	.0060	(.0001)	.0059	(.0054)	—	(.0054)	1.00	.54	12,589	.84 e,g	.43 e,g
September 30, 2008	1.00	.0277	(.0002)	.0275	(.0276)	(.0003)	(.0279)	1.00	2.83	5,564	1.06 g	2.54 g
September 30, 2007	1.00	.0436 h	— c	.0436	(.0439)	—	(.0439)	1.00	4.49	3,974	1.04 g	4.32 g, h
Class T
March 31, 2012 **	$1.00	.0001	— c	.0001	(.0001)	—	(.0001)	$1.00	— *d	$29,867	.10 *e	.01 *e
September 30, 2011	1.00	.0001	.0001	.0002	(.0001)	—	(.0001)	1.00	.01	33,941	.22 e	.01 e
September 30, 2010	1.00	.0001	(.0003)	(.0002)	(.0005)	—	(.0005)	1.00	.06	31,034	.32 e	— e,f
September 30, 2009	1.00	.0073	(.0001)	.0072	(.0067)	—	(.0067)	1.00	.67	39,088	.74 e,g	.64 e,g
September 30, 2008	1.00	.0302	(.0002)	.0300	(.0300)	(.0004)	(.0304)	1.00	3.08	20,037	.81 g	2.93 g
September 30, 2007	1.00	.0461 h	— c	.0461	(.0464)	—	(.0464)	1.00	4.75	14,743	.79 g	4.59 g, h

See notes to financial highlights at the end of this section.

The accompanying notes are an integral part of these financial statements.

26  27 

Financial highlights (Continued)

* Not annualized.

** Unaudited.

^a Total return assumes dividend reinvestment and does not reflect the effect of sales charges.

^b Includes amounts paid through expense offset arrangements (Note 2).

^c Amount represents less than $0.0001 per share.

^d Amount represents less than 0.01%.

^e Reflects a voluntary waiver of certain fund expenses in effect during the period relating to the enhancement of certain annualized net yields of the fund. As a result of such waivers, the expenses of each class reflect a reduction of the following amounts as a percentage of average net assets (Note 2):

	3/31/12	9/30/11	9/30/10	9/30/09
Class A	0.16%	0.28%	0.20%	0.02%
Class B	0.41	0.78	0.70	0.17
Class C	0.41	0.78	0.70	0.19
Class M	0.23	0.43	0.35	0.05
Class R	0.41	0.78	0.70	0.24
Class T	0.28	0.53	0.45	0.09

^f Amount represents less than 0.01% of average net assets.

^g Reflects an involuntary contractual expense limitation in effect during the period. For periods prior to September 30, 2009, certain fund expenses were waived in connection with the fund’s investment in Putnam Prime Money Market Fund. As a result of such limitation and/or waivers, the expenses of each class reflect a reduction of the following amounts:

	Percentage of
	average net assets
September 30, 2009	0.03%
September 30, 2008	<0.01
September 30, 2007	<0.01

^h Reflects a non-recurring reallocation of balance credits which amounted to $0.0003 per share and 0.03% of average net assets.

The accompanying notes are an integral part of these financial statements.

28

Notes to financial statements 3/31/12 (Unaudited)

Within the following Notes to financial statements, references to “State Street” represent State Street Bank and Trust Company, references to “the SEC” represent the Securities and Exchange Commission and references to “Putnam Management” represent Putnam Investment Management, LLC, the fund’s manager, an indirect wholly-owned subsidiary of Putnam Investments, LLC.

Putnam Money Market Fund (the fund) is a Massachusetts business trust, which is registered under the Investment Company Act of 1940, as amended, as a diversified open-end management investment company. The investment objective of the fund is to seek as high a rate of current income as Putnam Management believes is consistent with preservation of capital and maintenance of liquidity. The fund invests mainly in money market instruments that are high quality and have short-term maturities. The fund invests significantly in certificates of deposit, commercial paper (including asset-backed commercial paper), U.S. government debt and repurchase agreements, corporate obligations and bank acceptances. The fund may also invest in U.S. dollar denominated foreign securities of these types. Putnam Management may consider, among other factors, credit and interest rate risks, as well as general market conditions, when deciding whether to buy or sell investments.

The fund offers class A, class B, class C, class M, class R and class T shares. Each class of shares is sold without a front-end sales charge. Class A, class M, class R and class T shares also are generally not subject to a contingent deferred sales charge. In addition to the standard offering of class A shares, they are also sold to certain college savings plans and other Putnam funds. Class B shares convert to class A shares after approximately eight years and are subject to a contingent deferred sales charge on certain redemptions. Class C shares have a one-year 1.00% contingent deferred sales charge on certain redemptions and do not convert to class A shares. Class R shares are not available to all investors. The expenses for class A, class B, class C, class M, class R and class T shares may differ based on each class’ distribution fee, which is identified in Note 2.

In the normal course of business, the fund enters into contracts that may include agreements to indemnify another party under given circumstances. The fund’s maximum exposure under these arrangements is unknown as this would involve future claims that may be, but have not yet been, made against the fund. However, the fund’s management team expects the risk of material loss to be remote.

Note 1: Significant accounting policies

Investment income, realized gains and losses and expenses of the fund are borne pro-rata based on the relative net assets of each class to the total net assets of the fund, except that each class bears expenses unique to that class (including the distribution fees applicable to such classes). Each class votes as a class only with respect to its own distribution plan or other matters on which a class vote is required by law or determined by the Trustees. Shares of each class would receive their pro-rata share of the net assets of the fund, if the fund were liquidated. In addition, the Trustees declare separate dividends on each class of shares.

The following is a summary of significant accounting policies consistently followed by the fund in the preparation of its financial statements. The preparation of financial statements is in conformity with accounting principles generally accepted in the United States of America and requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements and the reported amounts of increases and decreases in net assets from operations. Actual results could differ from those estimates. Subsequent events after the Statement of assets and liabilities date through the date that the financial statements were issued have been evaluated in the preparation of the financial statements. Unless otherwise noted, the “reporting period” represents the period from October 1, 2011 through March 31, 2012.

Security valuation The valuation of the fund’s portfolio instruments is determined by means of the amortized cost method (which approximates market value) as set forth in Rule 2a–7 under the Investment Company Act of 1940. The amortized cost of an instrument is determined by valuing it at its original cost and thereafter amortizing any discount or premium from its face value at a constant rate until maturity and is generally categorized as a Level 2 security.

Investments in other open-end investment companies (excluding exchange traded funds), which are classified as Level 1 securities, are based on their net asset value. The net asset value of an investment company equals the total value of its assets less its liabilities and divided by the number of its outstanding shares. Shares are only valued as of the close of regular trading on the New York Stock Exchange each day that the exchange is open.

29

Joint trading account Pursuant to an exemptive order from the SEC, the fund may transfer uninvested cash balances into a joint trading account along with the cash of other registered investment companies and certain other accounts managed by Putnam Management. These balances may be invested in issues of short-term investments having maturities of up to 90 days.

Repurchase agreements The fund, or any joint trading account, through its custodian, receives delivery of the underlying securities, the market value of which at the time of purchase is required to be in an amount at least equal to the resale price, including accrued interest. Collateral for certain tri-party repurchase agreements is held at the counterparty’s custodian in a segregated account for the benefit of the fund and the counterparty. Putnam Management is responsible for determining that the value of these underlying securities is at all times at least equal to the resale price, including accrued interest. In the event of default or bankruptcy by the other party to the agreement, retention of the collateral may be subject to legal proceedings.

Security transactions and related investment income Security transactions are recorded on the trade date (the date the order to buy or sell is executed). Interest income is recorded on the accrual basis. Premiums and discounts from purchases of short-term investments are amortized/accreted at a constant rate until maturity. Gains or losses on securities sold are determined on the identified cost basis.

Interfund lending The fund, along with other Putnam funds, may participate in an interfund lending program pursuant to an exemptive order issued by the SEC. This program allows the fund to lend to other Putnam funds that permit such transactions. Interfund lending transactions are subject to each fund’s investment policies and borrowing and lending limits. Interest earned or paid on the interfund lending transaction will be based on the average of certain current market rates. During the reporting period, the fund did not utilize the program.

Line of credit The fund participates, along with other Putnam funds, in a $325 million unsecured committed line of credit and a $185 million unsecured uncommitted line of credit, both provided by State Street. Borrowings may be made for temporary or emergency purposes, including the funding of shareholder redemption requests and trade settlements. Interest is charged to the fund based on the fund’s borrowing at a rate equal to the Federal Funds rate plus 1.25% for the committed line of credit and the Federal Funds rate plus 1.30% for the uncommitted line of credit. A closing fee equal to 0.02% of the committed line of credit and $50,000 for the uncommitted line of credit has been paid by the participating funds. In addition, a commitment fee of 0.13% per annum on any unutilized portion of the committed line of credit is allocated to the participating funds based on their relative net assets and paid quarterly. During the reporting period, the fund had no borrowings against these arrangements.

Federal taxes It is the policy of the fund to distribute all of its taxable income within the prescribed time period and otherwise comply with the provisions of the Internal Revenue Code of 1986, as amended (the Code), applicable to regulated investment companies. It is also the intention of the fund to distribute an amount sufficient to avoid imposition of any excise tax under Section 4982 of the Code.

The fund is subject to the provisions of Accounting Standards Codification ASC 740 Income Taxes (ASC 740). ASC 740 sets forth a minimum threshold for financial statement recognition of the benefit of a tax position taken or expected to be taken in a tax return. The fund did not have a liability to record for any unrecognized tax benefits in the accompanying financial statements. No provision has been made for federal taxes on income, capital gains or unrealized appreciation on securities held nor for excise tax on income and capital gains. Each of the fund’s federal tax returns for the prior three fiscal years remains subject to examination by the Internal Revenue Service.

At September 30, 2011, the fund had a capital loss carryover of $1,381,629 available to the extent allowed by the Code to offset future net capital gain, if any. The amounts of the carryovers and the expiration dates are:

Loss carryover
Short-term	Long-term	Total	Expiration
$39,633	$—	$39,633	September 30, 2016
820,576	—	820,576	September 30, 2017
521,420	—	521,420	September 30, 2019

Under the recently enacted Regulated Investment Company Modernization Act of 2010, the fund will be permitted to carry forward capital losses incurred in taxable years beginning after December 22, 2010 for an unlimited period. However, any losses incurred during those future years will be required to be utilized prior to the losses

30

incurred in pre-enactment tax years. As a result of this ordering rule, pre-enactment capital loss carryforwards may be more likely to expire unused. Additionally, post-enactment capital losses that are carried forward will retain their character as either short-term or long-term capital losses rather than being considered all short-term as under previous law.

The aggregate identified cost on a financial reporting and tax basis is the same.

Distributions to shareholders Income dividends are recorded daily by the fund and are paid monthly. Distributions from capital gains, if any, are paid at least annually. The amount and character of income and gains to be distributed are determined in accordance with income tax regulations, which may differ from generally accepted accounting principles. Dividend sources are estimated at the time of declaration. Actual results may vary. Any non-taxable return of capital cannot be determined until final tax calculations are completed after the end of the fund’s fiscal year. Reclassifications are made to the fund’s capital accounts to reflect income and gains available for distribution (or available capital loss carryovers) under income tax regulations.

Note 2: Management fee, administrative services and other transactions

The fund pays Putnam Management a management fee (based on the fund’s average net assets and computed and paid monthly) at annual rates that may vary based on the average of the aggregate net assets of most open-end funds, as defined in the fund’s management contract, sponsored by Putnam Management. Such annual rates may vary as follows:

0.440%	of the first $5 billion,
0.390%	of the next $5 billion,
0.340%	of the next $10 billion,
0.290%	of the next $10 billion,
0.240%	of the next $50 billion,
0.220%	of the next $50 billion,
0.210%	of the next $100 billion and
0.205%	of any excess thereafter.

Putnam Management has contractually agreed, through June 30, 2012, to waive fees or reimburse the fund’s expenses to the extent necessary to limit the cumulative expenses of the fund, exclusive of brokerage, interest, taxes, investment-related expenses, extraordinary expenses and payments under the fund’s investor servicing contract, investment management contract and distribution plans, on a fiscal year-to-date basis to an annual rate of 0.20% of the fund’s average net assets over such fiscal year-to-date period. During the reporting period, the fund’s expenses were not reduced as a result of this limit.

Putnam Management may from time to time voluntarily undertake to waive fees and/or reimburse certain fund expenses in order to enhance the annualized net yield for the fund. Any such waiver or reimbursement would be voluntary and may be modified or discontinued by Putnam Management at any time without notice. During the reporting period, the fund’s expenses were reduced by $3,020,303 as a result of this limit, and the net yield at the close of the reporting period was 0.01%. This includes the following amounts per class of class specific distribution fees from the fund:

	Distribution fee waived
Class A	$—
Class B	60,449
Class C	72,571
Class M	22,195
Class R	47,408
Class T	39,464

Putnam Investments Limited (PIL), an affiliate of Putnam Management, is authorized by the Trustees to manage a separate portion of the assets of the fund as determined by Putnam Management from time to time. Putnam Management pays a quarterly sub-management fee to PIL for its services at an annual rate of 0.40% of the average net assets of the portion of the fund managed by PIL.

31

The fund reimburses Putnam Management an allocated amount for the compensation and related expenses of certain officers of the fund and their staff who provide administrative services to the fund. The aggregate amount of all such reimbursements is determined annually by the Trustees.

Custodial functions for the fund’s assets are provided by State Street. Custody fees are based on the fund’s asset level, the number of its security holdings and transaction volumes.

Putnam Investor Services, Inc., an affiliate of Putnam Management, provides investor servicing agent functions to the fund. Putnam Investor Services, Inc. received fees for investor servicing based on the fund’s retail asset level, the number of shareholder accounts in the fund and the level of defined contribution plan assets in the fund. Investor servicing fees will not exceed an annual rate of 0.32% of the fund’s average net assets. Prior to March 1, 2012, investor servicing fees could not exceed an annual rate of 0.375% of the fund’s average net assets. The amounts incurred for investor servicing agent functions during the reporting period are included in Investor servicing fees in the Statement of operations.

The fund has entered into expense offset arrangements with Putnam Investor Services, Inc. and State Street whereby Putnam Investor Services, Inc.’s and State Street’s fees are reduced by credits allowed on cash balances. For the reporting period, the fund’s expenses were reduced by $7,663 under the expense offset arrangements.

Each independent Trustee of the fund receives an annual Trustee fee, of which $1,382, as a quarterly retainer, has been allocated to the fund, and an additional fee for each Trustees meeting attended. Trustees also are reimbursed for expenses they incur relating to their services as Trustees.

The fund has adopted a Trustee Fee Deferral Plan (the Deferral Plan) which allows the Trustees to defer the receipt of all or a portion of Trustees fees payable on or after July 1, 1995. The deferred fees remain invested in certain Putnam funds until distribution in accordance with the Deferral Plan.

The fund has adopted an unfunded noncontributory defined benefit pension plan (the Pension Plan) covering all Trustees of the fund who have served as a Trustee for at least five years and were first elected prior to 2004. Benefits under the Pension Plan are equal to 50% of the Trustee’s average annual attendance and retainer fees for the three years ended December 31, 2005. The retirement benefit is payable during a Trustee’s lifetime, beginning the year following retirement, for the number of years of service through December 31, 2006. Pension expense for the fund is included in Trustee compensation and expenses in the Statement of operations. Accrued pension liability is included in Payable for Trustee compensation and expenses in the Statement of assets and liabilities. The Trustees have terminated the Pension Plan with respect to any Trustee first elected after 2003.

The fund has adopted distribution plans (the Plans) with respect to its class B, class C, class M, class R and class T shares pursuant to Rule 12b–1 under the Investment Company Act of 1940. The purpose of the Plans is to compensate Putnam Retail Management Limited Partnership, a wholly-owned subsidiary of Putnam Investments, LLC and Putnam Retail Management GP, Inc., for services provided and expenses incurred in distributing shares of the fund. The Plans provide for payments by the fund to Putnam Retail Management Limited Partnership at an annual rate of up to 0.75%, 1.00%, 1.00%, 1.00% and 0.35% of the average net assets attributable to class B, class C, class M, class R and class T shares, respectively. The Trustees have approved payment by the fund at an annual rate of 0.50%, 0.50%, 0.15%, 0.50% and 0.25% of the average net assets attributable to class B, class C, class M, class R and class T shares, respectively.

For the reporting period, Putnam Retail Management Limited Partnership, acting as underwriter, received net commissions of $30,670 and $7,100, respectively, in contingent deferred sales charges from redemptions of class B and class C shares purchased by exchange from another Putnam fund.

A deferred sales charge of up to 1.00% for class A and class T shares and up to 0.15% for class M shares may be assessed on certain redemptions. For the reporting period, Putnam Retail Management Limited Partnership, acting as underwriter, received no monies in contingent deferred sales charges from redemptions of class A, class M or class T shares purchased by exchange from another Putnam fund.

Note 3: Purchases and sales of securities

During the reporting period, cost of purchases and proceeds from sales (including maturities) of investment securities (all short-term obligations) aggregated $56,889,733,143 and $57,103,442,071, respectively.

32

Note 4: Capital shares

At the close of the reporting period, there was an unlimited number of shares of beneficial interest authorized. Transactions in capital shares were as follows:

	Six months ended 3/31/12		Year ended 9/30/11
Class A	Shares	Amount	Shares	Amount
Shares sold	443,983,842	$443,983,842	990,528,207	$990,528,207
Shares issued in connection with
reinvestment of distributions	70,450	70,450	213,881	213,881
	444,054,292	444,054,292	990,742,088	990,742,088
Shares repurchased	(640,000,331)	(640,000,331)	(1,382,829,728)	(1,382,829,728)
Net decrease	(195,946,039)	$(195,946,039)	(392,087,640)	$(392,087,640)
	Six months ended 3/31/12		Year ended 9/30/11
Class B	Shares	Amount	Shares	Amount
Shares sold	5,414,734	$5,414,734	18,097,439	$18,097,439
Shares issued in connection with
reinvestment of distributions	841	841	3,174	3,174
	5,415,575	5,415,575	18,100,613	18,100,613
Shares repurchased	(11,791,178)	(11,791,178)	(27,561,663)	(27,561,663)
Net decrease	(6,375,603)	$(6,375,603)	(9,461,050)	$(9,461,050)
	Six months ended 3/31/12		Year ended 9/30/11
Class C	Shares	Amount	Shares	Amount
Shares sold	12,505,354	$12,505,354	37,289,002	$37,289,002
Shares issued in connection with
reinvestment of distributions	1,216	1,216	2,891	2,891
	12,506,570	12,506,570	37,291,893	37,291,893
Shares repurchased	(16,527,179)	(16,527,179)	(28,200,918)	(28,200,918)
Net increase (decrease)	(4,020,609)	$(4,020,609)	9,090,975	$9,090,975
	Six months ended 3/31/12		Year ended 9/30/11
Class M	Shares	Amount	Shares	Amount
Shares sold	11,765,558	$11,765,558	27,735,752	$27,735,752
Shares issued in connection with
reinvestment of distributions	1,193	1,193	3,841	3,841
	11,766,751	11,766,751	27,739,593	27,739,593
Shares repurchased	(15,344,764)	(15,344,764)	(32,448,948)	(32,448,948)
Net decrease	(3,578,013)	$(3,578,013)	(4,709,355)	$(4,709,355)

33

	Six months ended 3/31/12		Year ended 9/30/11
Class R	Shares	Amount	Shares	Amount
Shares sold	7,466,349	$7,466,349	15,430,410	$15,430,410
Shares issued in connection with
reinvestment of distributions	913	913	2,274	2,274
	7,467,262	7,467,262	15,432,684	15,432,684
Shares repurchased	(6,122,965)	(6,122,965)	(13,202,800)	(13,202,800)
Net increase	1,344,297	$1,344,297	2,229,884	$2,229,884
	Six months ended 3/31/12		Year ended 9/30/11
Class T	Shares	Amount	Shares	Amount
Shares sold	7,223,055	$7,223,055	32,650,905	$32,650,905
Shares issued in connection with
reinvestment of distributions	1,462	1,462	4,465	4,465
	7,224,517	7,224,517	32,655,370	32,655,370
Shares repurchased	(11,305,081)	(11,305,081)	(29,736,404)	(29,736,404)
Net increase (decrease)	(4,080,564)	$(4,080,564)	2,918,966	$2,918,966

Note 5: Investment in Putnam Money Market Liquidity Fund

The fund invested in Putnam Money Market Liquidity Fund, an open-end management investment company managed by Putnam Management. Investments in Putnam Money Market Liquidity Fund are valued at its closing net asset value each business day. Income distributions earned by the fund are recorded as interest income in the Statement of operations and totaled $14,112 for the reporting period. During the reporting period, cost of purchases and proceeds of sales of investments in Putnam Money Market Liquidity Fund aggregated $10,000,000 and $107,046,017, respectively. Management fees charged to Putnam Money Market Liquidity Fund have been waived by Putnam Management.

Note 6: Market, credit and other risks

In the normal course of business, the fund trades financial instruments and enters into financial transactions where risk of potential loss exists due to changes in the market (market risk) or failure of the contracting party to the transaction to perform (credit risk). The fund may be exposed to additional credit risk that an institution or other entity with which the fund has unsettled or open transactions will default. Investments in foreign securities involve certain risks, including those related to economic instability, unfavorable political developments, and currency fluctuations, not present with domestic investments.

Note 7: New accounting pronouncements

In May 2011, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2011–04 “Fair Value Measurements and Disclosures (Topic 820) — Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. GAAP and IFRS”. ASU 2011–04 amends FASB Topic 820 “Fair Value Measurement” and seeks to develop common requirements for measuring fair value and for disclosing information about fair value measurements in accordance with GAAP. ASU 2011–04 is effective for fiscal years and interim periods beginning after December 15, 2011. The application of ASU 2011–04 will not have a material impact on the fund’s financial statements.

In December 2011, the FASB issued ASU No. 2011–11 “Disclosures about Offsetting Assets and Liabilities”. The update creates new disclosure requirements requiring entities to disclose both gross and net information for derivatives and other financial instruments that are either offset in the Statement of assets and liabilities or subject to an enforceable master netting arrangement or similar agreement. The disclosure requirements are effective for annual reporting periods beginning on or after January 1, 2013 and interim periods within those annual periods. Putnam Management is currently evaluating the application of ASU 2011–11 and its impact, if any, on the fund’s financial statements.

34

The Putnam family of funds

The following is a list of Putnam’s open-end mutual funds offered to the public. Investors should carefully consider the investment objective, risks, charges, and expenses of a fund before investing. For a prospectus, or a summary prospectus if available, containing this and other information for any Putnam fund or product, call your financial advisor at 1-800-225-1581 and ask for a prospectus. Please read the prospectus carefully before investing.

Growth	Income
Growth Opportunities Fund	American Government Income Fund
International Growth Fund	Diversified Income Trust
Multi-Cap Growth Fund	Floating Rate Income Fund
Small Cap Growth Fund	Global Income Trust
Voyager Fund	High Yield Advantage Fund
	High Yield Trust
Blend	Income Fund
Asia Pacific Equity Fund	Money Market Fund*
Capital Opportunities Fund	Short Duration Income Fund
Capital Spectrum Fund	U.S. Government Income Trust
Emerging Markets Equity Fund
Equity Spectrum Fund	Tax-free income
Europe Equity Fund	AMT-Free Municipal Fund
Global Equity Fund	Tax Exempt Income Fund
International Capital Opportunities Fund	Tax Exempt Money Market Fund*
International Equity Fund	Tax-Free High Yield Fund
Investors Fund
Multi-Cap Core Fund	State tax-free income funds:
Research Fund	Arizona, California, Massachusetts, Michigan,
	Minnesota, New Jersey, New York, Ohio,
Value	and Pennsylvania.
Convertible Securities Fund
Equity Income Fund	Absolute Return
George Putnam Balanced Fund	Absolute Return 100 Fund
The Putnam Fund for Growth and Income	Absolute Return 300 Fund
International Value Fund	Absolute Return 500 Fund
Multi-Cap Value Fund	Absolute Return 700 Fund
Small Cap Value Fund

* An investment in a money market fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Although the fund seeks to preserve the value of your investment at $1.00 per share, it is possible to lose money by investing in the fund.

35

Global Sector	Putnam RetirementReady Funds — portfolios
Global Consumer Fund	with automatically adjusting allocations to
Global Energy Fund	stocks, bonds, and money market instruments,
Global Financials Fund	becoming more conservative over time.
Global Health Care Fund
Global Industrials Fund	RetirementReady 2055 Fund
Global Natural Resources Fund	RetirementReady 2050 Fund
Global Sector Fund	RetirementReady 2045 Fund
Global Technology Fund	RetirementReady 2040 Fund
Global Telecommunications Fund	RetirementReady 2035 Fund
Global Utilities Fund	RetirementReady 2030 Fund
	RetirementReady 2025 Fund
Asset Allocation	RetirementReady 2020 Fund
Putnam Global Asset Allocation Funds —	RetirementReady 2015 Fund
portfolios with allocations to stocks, bonds,
and money market instruments that are	Putnam Retirement Income Lifestyle
adjusted dynamically within specified ranges	Funds — portfolios with managed
as market conditions change.	allocations to stocks, bonds, and money
	market investments to generate
Dynamic Asset Allocation Balanced Fund	retirement income.
Prior to November 30, 2011, this fund was known as
Putnam Asset Allocation: Balanced Portfolio.	Retirement Income Fund Lifestyle 1
Dynamic Asset Allocation	Prior to June 16, 2011, this fund was known as
Conservative Fund	Putnam RetirementReady Maturity Fund.
Prior to November 30, 2011, this fund was known as	Retirement Income Fund Lifestyle 2
Putnam Asset Allocation: Conservative Portfolio.	Retirement Income Fund Lifestyle 3
Dynamic Asset Allocation Growth Fund	Prior to June 16, 2011, this fund was known as
Prior to November 30, 2011, this fund was known as	Putnam Income Strategies Fund.
Putnam Asset Allocation: Growth Portfolio.
Dynamic Risk Allocation Fund

A short-term trading fee of 1% may apply to redemptions or exchanges from certain funds within the time period specified in the fund's prospectus.

Check your account balances and the most recent month-end performance in the Individual Investors section at putnam.com.

36

Fund information

Founded 75 years ago, Putnam Investments was built around the concept that a balance between risk and reward is the hallmark of a well-rounded financial program. We manage over 100 funds across income, value, blend, growth, asset allocation, absolute return, and global sector categories.

Investment Manager	Elizabeth T. Kennan	Mark C. Trenchard
Putnam Investment	Kenneth R. Leibler	Vice President and
Management, LLC	Robert E. Patterson	BSA Compliance Officer
One Post Office Square	George Putnam, III
Boston, MA 02109	Robert L. Reynolds	Robert T. Burns
	W. Thomas Stephens	Vice President and
Investment Sub-Manager		Chief Legal Officer
Putnam Investments Limited	Officers
57–59 St James’s Street	Robert L. Reynolds	James P. Pappas
London, England SW1A 1LD	President	Vice President
Marketing Services	Jonathan S. Horwitz	Judith Cohen
Putnam Retail Management	Executive Vice President,	Vice President, Clerk and
One Post Office Square	Principal Executive	Assistant Treasurer
Boston, MA 02109	Officer, Treasurer and
	Compliance Liaison	Michael Higgins
Custodian		Vice President, Senior Associate
State Street Bank	Steven D. Krichmar	Treasurer and Assistant Clerk
and Trust Company	Vice President and
	Principal Financial Officer	Nancy E. Florek
Legal Counsel		Vice President, Assistant Clerk,
Ropes & Gray LLP	Janet C. Smith	Assistant Treasurer and
	Vice President, Assistant	Proxy Manager
Trustees	Treasurer and Principal
Jameson A. Baxter, Chair	Accounting Officer	Susan G. Malloy
Ravi Akhoury		Vice President and
Barbara M. Baumann	Robert R. Leveille	Assistant Treasurer
Charles B. Curtis	Vice President and
Robert J. Darretta	Chief Compliance Officer
John A. Hill
Paul L. Joskow

This report is for the information of shareholders of Putnam Money Market Fund. It may also be used as sales literature when preceded or accompanied by the current prospectus, the most recent copy of Putnam’s Quarterly Performance Summary, and Putnam’s Quarterly Ranking Summary. For more recent performance, please visit putnam.com. Investors should carefully consider the investment objectives, risks, charges, and expenses of a fund, which are described in its prospectus. For this and other information or to request a prospectus or summary prospectus, call 1-800-225-1581 toll free. Please read the prospectus carefully before investing. The fund’s Statement of Additional Information contains additional information about the fund’s Trustees and is available without charge upon request by calling 1-800-225-1581.

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:

The registrant’s schedule of investments in unaffiliated issuers is included in the report to shareholders in Item 1 above.

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

Not applicable

Item 8. Portfolio Managers of Closed-End Investment Companies

Not Applicable

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

Not applicable

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

Not applicable

Item 11. Controls and Procedures:

(a) The registrant’s principal executive officer and principal financial officer have concluded, based on their evaluation of the effectiveness of the design and operation of the registrant’s disclosure controls and procedures as of a date within 90 days of the filing date of this report, that the design and operation of such procedures are generally effective to provide reasonable assurance that information required to be disclosed by the registrant in this report is recorded, processed, summarized and reported within the time periods specified in the Commission’s rules and forms.

(b) Changes in internal control over financial reporting: Not applicable

Item 12. Exhibits:

(a)(1) Not applicable

(a)(2) Separate certifications for the principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(a) under the Investment Company Act of 1940, as amended, are filed herewith.

(b) The certifications required by Rule 30a-2(b) under the Investment Company Act of 1940, as amended, are filed herewith.

Putnam Money Market Fund

By (Signature and Title):

/s/Janet C. Smith
Janet C. Smith
Principal Accounting Officer

Date: May 29, 2012

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 (Signature and Title):

/s/Jonathan S. Horwitz
Jonathan S. Horwitz
Principal Executive Officer

Date: May 29, 2012

By (Signature and Title):

/s/Steven D. Krichmar
Steven D. Krichmar
Principal Financial Officer

Date: May 29, 2012