<Page>
-----------------------------
OMB APPROVAL
-----------------------------
OMB Number: 3235-0570
Expires: November 30, 2005
Estimated average burden
hours per response....... 5.0
-----------------------------
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 811-07678
---------------------------------------------
American Municipal Income Portfolio Inc.
- -------------------------------------------------------------------------------
(Exact name of registrant as specified in charter)
800 Nicollet Mall, Minneapolis, MN 55402
- -------------------------------------------------------------------------------
(Address of principal executive offices) (Zip code)
Robert H. Nelson 800 Nicollet Mall, Minneapolis, MN 55402
- -------------------------------------------------------------------------------
(Name and address of agent for service)
Registrant's telephone number, including area code: 800-677-3863
----------------------------
Date of fiscal year end: January 31, 2004
--------------------------
Date of reporting period: July 31, 2003
-------------------------
Form N-CSR is to be used by management investment companies to file reports
with the Commission not later than 10 days after the transmission to
stockholders of any report that is required to be transmitted to stockholders
under Rule 30e-1 under the Investment Company Act of 1940 (17 CFR 270.30e-1).
The Commission may use the information provided on Form N-CSR in its
regulatory, disclosure review, inspection, and policymaking roles.
A registrant is required to disclose the information specified by Form N-CSR,
and the Commission will make this information public. A registrant is not
required to respond to the collection of information contained in Form N-CSR
unless the Form displays a currently valid Office of Management and Budget
("OMB") control number. Please direct comments concerning the accuracy of the
information collection burden estimate and any suggestions for reducing the
burden to Secretary, Securities and Exchange Commission, 450 Fifth Street,
NW, Washington, DC 20549-0609. The OMB has reviewed this collection of
information under the clearance requirements of 44 U.S.C. Section 3507.
<Page>
Item 1. Report to Shareholders
<Page>
[FIRST AMERICAN(TM) LOGO]
AMERICAN MUNICIPAL
INCOME PORTFOLIO
XAA
JULY 31, 2003
SEMIANNUAL REPORT
<Page>
[FIRST AMERICAN(TM) LOGO]
AMERICAN MUNICIPAL
INCOME PORTFOLIO
HIS RICH LEGACY AS PATRIOT AND LEADER IS WIDELY RECOGNIZED AS EMBODYING THE
SOUND JUDGMENT, RELIABILITY, AND STRATEGIC VISION THAT ARE CENTRAL TO OUR BRAND.
FASHIONED IN A STYLE REMINISCENT OF AN 18TH CENTURY ENGRAVING, THE ILLUSTRATION
CONVEYS THE SYMBOLIC STRENGTH AND VITALITY OF WASHINGTON, WHICH ARE ATTRIBUTES
THAT WE VALUE AT FIRST AMERICAN.
TABLE OF CONTENTS
<Table>
1 Financial Statements
4 Notes to Financial Statements
13 Schedule of Investments
22 Shareholder Update
</Table>
NOT FDIC INSURED NO BANK GUARANTEE MAY LOSE VALUE
<Page>
FINANCIAL STATEMENTS (Unaudited)
STATEMENT OF ASSETS AND LIABILITIES July 31, 2003
<Table>
ASSETS:
Investments in securities at market value* (note 2) $ 129,136,003
Accrued interest receivable 1,372,636
Other assets 8,717
-------------
Total assets 130,517,356
-------------
LIABILITIES:
Preferred share dividends payable (note 3) 4,130
Payable for investment securities purchased 2,516,600
Accrued investment management fee (note 5) 39,118
Accrued administrative fee (note 5) 22,353
Accrued remarketing agent fee (note 5) 5,247
Other accrued expenses 16,950
-------------
Total liabilities 2,604,398
-------------
Preferred shares, at liquidation value 43,500,000
-------------
Net assets applicable to outstanding common shares $ 84,412,958
=============
NET ASSETS APPLICABLE TO OUTSTANDING COMMON SHARES CONSIST OF:
Common shares and additional paid-in capital $ 80,531,021
Undistributed net investment income 1,439,627
Accumulated net realized loss on investments (1,485,856)
Unrealized appreciation of investments 3,928,166
-------------
Net assets applicable to outstanding common shares $ 84,412,958
=============
*Investments in securities at identified cost $ 125,207,837
=============
NET ASSET VALUE AND MARKET PRICE OF COMMON SHARES:
Net assets applicable to outstanding common shares $ 84,412,958
Common shares outstanding (authorized 200 million shares of
$0.01 par value) 5,756,267
Net asset value per share $ 14.66
Market price per share $ 14.45
LIQUIDATION PREFERENCE OF PREFERRED SHARES (NOTE 3):
Preferred shares outstanding (authorized one million shares) 1,740
Liquidation preference per share $ 25,000
</Table>
SEE ACCOMPANYING NOTES TO FINANCIAL STATEMENTS.
2003 SEMIANNUAL REPORT AMERICAN MUNICIPAL INCOME PORTFOLIO
1
<Page>
STATEMENT OF OPERATIONS For the Six Months Ended July 31, 2003
<Table>
INCOME:
Interest $ 3,471,225
Dividends from affiliated money market fund 12,542
-------------
Total investment income 3,483,767
-------------
EXPENSES (NOTE 5):
Investment management fee 229,925
Administrative fee 131,386
Remarketing agent fee 55,997
Custodian fees 9,854
Transfer agent fees 23,032
Registration fees 11,750
Reports to shareholders 21,567
Directors' fees 4,896
Audit and legal fees 25,101
Professional fees 11,696
Other expenses 3,312
-------------
Total expenses 528,516
-------------
Net investment income 2,955,251
-------------
NET REALIZED AND UNREALIZED GAINS (LOSSES) ON INVESTMENTS:
Net realized gain on investments in securities (note 4) 554,892
Net change in unrealized appreciation or depreciation
of investments (3,290,195)
-------------
Net loss on investments (2,735,303)
-------------
DISTRIBUTIONS TO PREFERRED SHAREHOLDERS (NOTE 2):
From net investment income (213,922)
-------------
Net increase in net assets applicable to common shares
resulting from operations $ 6,026
=============
</Table>
SEE ACCOMPANYING NOTES TO FINANCIAL STATEMENTS.
2
<Page>
STATEMENTS OF CHANGES IN NET ASSETS
<Table>
<Caption>
SIX MONTHS
ENDED
7/31/03 YEAR ENDED
(UNAUDITED) 1/31/03
------------ ------------
OPERATIONS:
Net investment income $ 2,955,251 $ 6,174,302
Net realized gain on investments in securities 554,892 968,258
Net change in unrealized appreciation or depreciation of investments (3,290,195) 1,336,688
Distributions to preferred shareholders (note 2):
From net investment income (213,922) (551,664)
------------ ------------
Net increase in net assets applicable to common shares resulting
from operations 6,026 7,927,584
------------ ------------
DISTRIBUTIONS TO COMMON SHAREHOLDERS (NOTE 2):
From net investment income (2,693,933) (5,244,420)
------------ ------------
Total increase (decrease) in net assets applicable to common shares (2,687,907) 2,683,164
Net assets applicable to common shares at beginning of period 87,100,865 84,417,701
------------ ------------
Net assets applicable to common shares at end of period $ 84,412,958 $ 87,100,865
============ ============
Undistributed net investment income $ 1,439,627 $ 1,392,231
============ ============
</Table>
SEE ACCOMPANYING NOTES TO FINANCIAL STATEMENTS.
3
<Page>
NOTES TO FINANCIAL STATEMENTS (Unaudited)
(1) ORGANIZATION American Municipal Income Portfolio Inc. (the "Fund") is
registered under the Investment Company Act of 1940 (as
amended) as a diversified, closed-end management investment
company. The Fund invests in a diverse range of municipal
securities rated investment grade or unrated and deemed
to be of comparable quality by the Fund's advisor at the
time of purchase. These securities may include municipal
derivative securities, such as inverse floating rate and
inverse interest-only municipal securities. The Fund's
investments also may include futures contracts, options on
futures contracts, options, and interest rate swaps, caps,
and floors. Although the Fund is authorized to invest in
the financial instruments mentioned in the preceding
sentence, and may do so in the future, the Fund did not
make any such investments during the six months ended
July 31, 2003. Fund shares are listed on the New York
Stock Exchange under the symbol XAA.
(2) SUMMARY OF SECURITY VALUATIONS
SIGNIFICANT Portfolio securities for which market quotations are readily
ACCOUNTING available are valued at current market value. If market
POLICIES quotations or valuations are not readily available, or if
such quotations or valuations are believed to be inaccurate,
unreliable, or not reflective of market value, portfolio
securities are valued according to procedures adopted by the
Fund's board of directors in good faith at "fair value,"
that is, a price that the Fund might reasonably expect to
receive for the security or other asset upon its current
sale. As of July 31, 2003, the Fund had no fair-valued
securities.
Security valuations for the Fund's investments are furnished
by one or more independent pricing services that have been
approved by the Fund's board of directors. Investments in
equity securities that are traded on a national securities
exchange (or reported on the Nasdaq national market system)
are stated at the last quoted sales price if readily
available for such securities on each business day. For
securities traded on the Nasdaq national market system, the
Fund utilizes the Nasdaq Official
4
<Page>
Closing Price which compares the last trade to the bid/ask
price of a security. If the last trade falls with in the
bid/ask range, then that price will be the closing price. If
the last trade is outside the bid/ask range, and falls above
the ask, the ask price will be the closing price. If the
last trade is below the bid, the bid will be the closing
price. Other equity securities traded in the
over-the-counter market and listed equity securities for
which no sale was reported on that date are stated at the
last quoted bid price.
Debt obligations exceeding 60 days to maturity are valued by
an independent pricing service. The pricing service may
employ methodologies that utilize actual market
transactions, broker-dealer supplied valuations, or other
formula driven valuation techniques. These techniques
generally consider such factors as yields or prices of bonds
of comparable quality, type of issue, coupon, maturity,
ratings, and general market conditions. Securities for which
prices are not available from an independent pricing service
but where an active market exists are valued using market
quotations obtained from one or more dealers that make
markets in the securities or from a widely-used quotation
system. Debt obligations with 60 days or less remaining
until maturity may be valued at their amortized cost which
approximates market value.
SECURITIES TRANSACTIONS AND INVESTMENT INCOME
Securities transactions are accounted for on the date
securities are purchased or sold. Realized gains and losses
are calculated on the identified-cost basis. Dividend income
is recorded on the ex-dividend date. Interest income,
including accretion of bond discounts and amortization of
premiums, is recorded on an accrual basis.
INVERSE FLOATERS
As part of its investment strategy, the Fund may invest in
certain securities for which the potential income return is
5
<Page>
inversely related to changes in a floating interest rate
("inverse floaters"). In general, income on inverse floaters
will decrease when short-term interest rates increase and
increase when short-term interest rates decrease.
Investments in inverse floaters may be characterized as
derivative securities and may subject the Fund to the risks
of reduced or eliminated interest payments and losses of
invested principal. In addition, inverse floaters have the
effect of providing investment leverage and, as a result,
the market value of such securities will generally be more
volatile than that of fixed-rate, tax-exempt securities. To
the extent the Fund invests in inverse floaters, the net
asset value of the Fund's shares may be more volatile than
if the Fund did not invest in such securities. As of July
31, 2003, the Fund had no outstanding investments in inverse
floaters.
SECURITIES PURCHASED ON A WHEN-ISSUED BASIS
Delivery and payment for securities that have been purchased
by the Fund on a when-issued or forward-commitment basis can
take place a month or more after the transaction date.
During this period, such securities do not earn interest,
are subject to market fluctuation, and may increase or
decrease in value prior to their delivery. The Fund
segregates, with its custodian, assets with a market value
equal to the amount of its purchase commitments. The
purchase of securities on a when-issued or
forward-commitment basis may increase the volatility of the
Fund's net asset value if the Fund makes such purchases
while remaining substantially fully invested. As of July 31,
2003, the Fund had no outstanding when-issued or
forward-commitments.
FEDERAL TAXES
The Fund intends to comply with the requirements of the
Internal Revenue Code applicable to regulated
6
<Page>
investment companies and not be subject to federal income
tax. Therefore, no income tax provision is required. The
Fund also intends to distribute its taxable net investment
income and realized gains, if any, to avoid the payment of
any federal excise taxes.
Net investment income and net realized gains and losses may
differ for financial statement and tax purposes primarily
because of market discount amortization. The character of
distributions made during the year from net investment
income or net realized gains may differ from its ultimate
characterization for federal income tax purposes. In
addition, due to the timing of dividend distributions, the
fiscal year in which amounts are distributed may differ from
the year that the income or realized gains or losses were
recorded by the Fund.
The tax character of common and preferred share
distributions paid during the six months ended July 31, 2003
and the fiscal year ended January 31, 2003 was as follows:
<Table>
<Caption>
7/31/03 1/31/03
----------- -----------
Distributions paid from:
Tax exempt income $ 2,907,855 $ 5,793,355
Ordinary income -- 7,061
----------- -----------
$ 2,907,855 $ 5,800,416
=========== ===========
</Table>
At January 31, 2003, the Fund's most recently completed
fiscal year end, the components of accumulated earnings on a
tax basis were as follows:
<Table>
Undistributed tax exempt income $ 1,295,401
Undistributed ordinary income 16,257
Accumulated capital losses (2,040,748)
Unrealized appreciation 7,298,934
------------
Accumulated earnings $ 6,569,844
============
</Table>
7
<Page>
DISTRIBUTIONS TO SHAREHOLDERS
Distributions from net investment income are made monthly
for common shareholders and weekly for preferred
shareholders. Common share distributions are recorded as of
the close of business on the ex-dividend date and preferred
share dividends are accrued daily. Net realized gains
distributions, if any, will be made at least annually.
Distributions are payable in cash or, for common
shareholders pursuant to the Fund's dividend reinvestment
plan, reinvested in additional common shares of the Fund.
Under the dividend reinvestment plan, common shares will be
purchased in the open market.
REPURCHASE AGREEMENTS AND OTHER SHORT-TERM SECURITIES
The Fund, along with other affiliated registered investment
companies, may transfer uninvested cash balances into a
joint trading account, the daily aggregate balance of which
is invested in repurchase agreements secured by U.S.
government or agency obligations. Securities pledged as
collateral for all individual and joint repurchase
agreements are held by the Fund's custodian bank until
maturity of the repurchase agreement. Provisions for all
agreements ensure that the daily market value of the
collateral is in excess of the repurchase amount, including
accrued interest, to protect the Fund in the event of a
default. In addition to repurchase agreements, the Fund may
invest in money market funds advised by the Fund's advisor.
USE OF ESTIMATES
The preparation of financial statements in conformity with
accounting principles generally accepted in the United
States requires management to make estimates and assumptions
that affect the reported amounts in the financial
statements. Actual results could differ from these
estimates.
8
<Page>
(3) REMARKETED As of July 31, 2003, the Fund had 1,740 remarketed preferred
PREFERRED shares (870 shares in class "T" and 870 shares in class
SHARES "TH") ("RP(R)") outstanding with a liquidation preference of
$25,000 per share. The dividend rate on the RP(R) is
adjusted every seven days (on Tuesdays for class "T" and on
Thursdays for class "TH"), as determined by the remarketing
agent. On July 31, 2003, the dividend rates were 0.70% and
0.79% for class "T" and "TH," respectively.
RP(R) is a registered trademark of Merrill Lynch & Company
("Merrill Lynch").
(4) INVESTMENT Cost of purchases and proceeds from sales of securities,
SECURITY other than temporary investments in short-term securities,
TRANSACTIONS for the six months ended July 31, 2003, aggregated
$16,641,626 and $23,364,657, respectively.
(5) EXPENSES INVESTMENT MANAGEMENT AND ADMINISTRATIVE FEES
Pursuant to an investment advisory agreement (the
"Agreement"), U.S. Bancorp Asset Management, Inc. ("USBAM"),
a subsidiary of U.S. Bank National Association ("U.S.
Bank"), manages the Fund's assets and furnishes related
office facilities, equipment, research, and personnel. The
Agreement provides USBAM with a monthly investment
management fee in an amount equal to an annualized
percentage of 0.35% of the Fund's average weekly net assets
(computed by subtracting liabilities, which exclude
preferred shares, from the value of the total assets of the
Fund). For its fee, USBAM provides investment advice and, in
general, conducts the management and investment activities
of the Fund.
Pursuant to a co-administration agreement (the
"Co-Administration Agreement"), USBAM serves as
co-administrator for the Fund (U.S. Bancorp Fund Services,
LLC, a subsidiary of U.S. Bancorp, is also co-administrator
9
<Page>
but currently has no functional responsibilities related to
the Fund) (collectively the "Administrators") and provides
administrative services, including legal and shareholder
services, to the Fund. Under this Co-Administration
Agreement, the Administrators receive a monthly fee in an
amount equal to an annualized rate of 0.20% of the Fund's
average weekly net assets (computed by subtracting
liabilities, which exclude preferred shares, from the value
of the total assets of the Fund). For its fee, the
Administrators provide numerous services to the Fund,
including, but not limited to, handling the general business
affairs, financial and regulatory reporting, and various
record-keeping services. Separate from the Co-Administration
Agreement, USBAM (from its own resources) has retained SEI
Investments Inc. as a sub-administrator to perform net asset
value calculations.
The Fund may invest in money market funds that are series of
First American Funds, Inc. ("FAF"), subject to certain
limitations. The terms of such investments are identical to
those made by non-related entities except that, to avoid
duplicative investment advisory fees, USBAM reimburses the
Fund an amount equal to the investment advisory fee paid by
FAF to USBAM related to such investments. For financial
statement purposes, this reimbursement is recorded as
investment income.
REMARKETING AGENT FEE
The Fund has entered into a remarketing agreement with
Merrill Lynch (the "Remarketing Agent"). The remarketing
agreement provides the Remarketing Agent with a monthly fee
in an amount equal to an annualized rate of 0.25% of the
Fund's average amount of RP(R) outstanding. For its fee, the
Remarketing Agent will remarket shares of RP(R) tendered to
it on behalf of shareholders and will determine the
applicable dividend rate for each seven-day dividend period.
10
<Page>
OTHER FEES AND EXPENSES
In addition to the investment management, administrative,
and remarketing agent fees, the Fund is responsible for
paying most other operating expenses, including: outside
directors' fees and expenses, custodian fees, registration
fees, printing and shareholder reports, transfer agent fees
and expenses, legal, auditing, and accounting services,
insurance, interest, taxes, and other miscellaneous
expenses.
During the six months ended July 31, 2003, fees for custody
services were paid to U.S. Bank.
(6) CAPITAL LOSS For federal income tax purposes, the Fund had capital loss
CARRYOVER carryovers at January 31, 2003, the Fund's most recently
completed fiscal year end, which, if not offset by
subsequent capital gains, will expire on the Fund's fiscal
year-ends as indicated below.
<Table>
<Caption>
CAPITAL LOSS
CARRYOVER EXPIRATION
------------- ----------
$ 1,478,320 2004
216,201 2008
346,227 2009
-----------
$ 2,040,748
===========
</Table>
11
<Page>
(7) FINANCIAL Per-share data for an outstanding common share throughout
HIGHLIGHTS each period and selected information for each period are as
follows:
<Table>
<Caption>
SIX MONTHS
ENDED YEAR ENDED JANUARY 31,
7/31/03 ------------------------------------------------------------
(UNAUDITED) 2003 2002 2001 2000 1999
----------- -------- -------- -------- -------- --------
PER-SHARE DATA
Net asset value, common shares,
beginning of period $ 15.13 $ 14.67 $ 14.50 $ 13.17 $ 15.43 $ 15.07
------- -------- -------- -------- -------- --------
Operations:
Net investment income 0.51 1.07 1.04 1.15 1.03 1.02
Net realized and unrealized gains
(losses) on investments (0.48) 0.40 0.12 1.27 (2.27) 0.36
Distributions to preferred shareholders:
From net investment income (0.04) (0.10) (0.18) (0.30) (0.25) (0.27)
------- -------- -------- -------- -------- --------
Total from operations (0.01) 1.37 0.98 2.12 (1.49) 1.11
------- -------- -------- -------- -------- --------
Distributions to common shareholders:
From net investment income (0.46) (0.91) (0.81) (0.79) (0.77) (0.75)
------- -------- -------- -------- -------- --------
Net asset value, common shares, end of
period $ 14.66 $ 15.13 $ 14.67 $ 14.50 $ 13.17 $ 15.43
======= ======== ======== ======== ======== ========
Market value, common shares, end of
period $ 14.45 $ 14.60 $ 14.02 $ 13.80 $ 11.75 $ 14.00
======= ======== ======== ======== ======== ========
SELECTED INFORMATION
Total return, common shares, net asset
value (a) (0.13)% 9.58% 6.92% 16.58% (9.88)% 7.62%
Total return, common shares,
market value (b) 2.15% 11.06% 7.77% 25.44% (10.81)% 10.07%
Net assets applicable to common shares
at end of period (in millions) $ 84 $ 87 $ 84 $ 83 $ 75 $ 88
Ratio of expenses to average weekly net
assets applicable to common shares (c) 1.20%(e) 1.23% 1.17% 1.23% 1.20% 1.13%
Ratio of net investment income to
average weekly net assets applicable
to common shares (c) 6.70%(e) 7.19% 7.11% 8.00% 7.82% 6.62%
Portfolio turnover rate (excluding
short-term securities) 13% 18% 9% 35% 10% 19%
Remarketed preferred shares outstanding,
end of period (in millions) $ 44 $ 44 $ 44 $ 44 $ 44 $ 44
Asset coverage per preferred share (in
thousands) (d) $ 74 $ 75 $ 74 $ 73 $ 69 $ 76
Liquidation preference and market value
per remarketed preferred
share (in thousands) $ 25 $ 25 $ 25 $ 25 $ 25 $ 25
</Table>
(a) ASSUMES REINVESTMENT OF DISTRIBUTIONS AT NET ASSET VALUE.
(b) ASSUMES REINVESTMENT OF DISTRIBUTIONS AT ACTUAL PRICES PURSUANT TO THE
FUND'S DIVIDEND REINVESTMENT PLAN.
(c) RATIOS DO NOT REFLECT THE EFFECT OF DIVIDEND PAYMENTS TO PREFERRED
SHAREHOLDERS; INCOME RATIOS REFLECT INCOME EARNED ON ASSETS ATTRIBUTABLE TO
PREFERRED SHARES, WHERE APPLICABLE.
(d) REPRESENTS NET ASSETS APPLICABLE TO COMMON SHARES PLUS PREFERRED SHARES AT
LIQUIDATION VALUE DIVIDED BY PREFERRED SHARES OUTSTANDING.
(e) ANNUALIZED.
12
<Page>
SCHEDULE OF INVESTMENTS (Unaudited)
<Table>
<Caption>
JULY 31, 2003
PRINCIPAL MARKET
DESCRIPTION OF SECURITY AMOUNT VALUE (a)
- ----------------------------------------------------------------- ------------- -------------
(PERCENTAGES OF EACH INVESTMENT CATEGORY RELATE TO NET
ASSETS APPLICABLE TO OUTSTANDING COMMON SHARES)
MUNICIPAL LONG-TERM SECURITIES (138.8%):
ARIZONA (6.2%):
Douglas Community Housing
(Callable 1/20/10 at 102),
6.13%, 7/20/41 $ 995,000 $ 1,017,716
Gilbert Industrial Development Authority
(Callable 2/1/09 at 102),
5.85%, 2/1/19 1,000,000 957,020
Pima County United School District (FGIC),
8.38%, 7/1/13 2,450,000 (b) 3,256,760
-------------
5,231,496
-------------
CALIFORNIA (2.2%):
State General Obligation
(Callable 2/1/13 at 100), 5.00%, 2/1/21 1,500,000 1,410,645
Vernon California Electrical System
(Callable 4/1/08 at 100),
5.50%, 4/1/23 500,000 488,220
-------------
1,898,865
-------------
COLORADO (18.0%):
E-470 Public Highway, Zero-Coupon Bond,
5.45%, 9/1/32 30,000,000 (g) 5,534,100
Educational and Cultural Facilities Authority
(Callable 12/1/11 at 100),
7.25%, 12/1/30 2,000,000 2,045,440
Educational and Cultural Facilities Authority
(Callable 9/15/11 at 100),
7.25%, 9/15/30 1,000,000 1,022,930
Northwest Parkway Public Highway Authority,
Zero-Coupon Bond (AMBAC)
(Callable 6/15/11 at 33.46),
6.29%, 6/15/29 5,000,000 (b)(g) 1,047,500
State Health Facilities Authority
(Callable 10/1/12 at 100),
5.90%, 10/1/27 1,300,000 1,263,392
State Health Facilities Authority
(Callable 12/1/12 at 101),
6.13%, 12/1/33 1,000,000 958,130
State Multifamily Housing and Financial Authority
(Callable 4/1/12 at 100),
5.70%, 10/1/42 2,750,000 2,781,240
</Table>
SEE ACCOMPANYING NOTES TO SCHEDULE OF INVESTMENTS.
13
<Page>
<Table>
<Caption>
PRINCIPAL MARKET
DESCRIPTION OF SECURITY AMOUNT VALUE (a)
- ----------------------------------------------------------------- ------------- -------------
Water Reserve and Power Development
(Callable 9/1/06 at 101),
5.90%, 9/1/16 $ 500,000 $ 551,905
-------------
15,204,637
-------------
FLORIDA (0.6%):
Capital TR Agency Multifamily Housing
(Callable 6/1/11 at 102),
5.75%, 6/1/23 500,000 481,645
-------------
GEORGIA (10.9%):
Municipal Electrical Authority (FGIC)
(Escrowed to maturity),
6.50%, 1/1/12 8,000,000 (b)(c) 9,220,000
-------------
ILLINOIS (9.6%):
Chicago State University Revenue (MBIA)
(Prerefunded to 12/1/04 at 102),
6.00%, 12/1/12 1,000,000 (b)(e) 1,085,020
Health Facility Authority -- Lutheran General Hospital,
7.00%, 4/1/08 1,000,000 1,134,980
Health Facility Authority -- Lutheran General Hospital,
7.00%, 4/1/14 500,000 595,565
Kane County School District (FGIC)
(Prerefunded to 2/1/05 at 100),
5.75%, 2/1/15 1,000,000 (b)(e) 1,065,170
Metropolitan Pier and Exposition Authority,
Convertible, Zero-Coupon Bond (MBIA),
5.32%, 6/15/23 6,115,000 (b)(g) 2,767,037
Rockford Multifamily Housing Revenue, AMT
(Callable 1/20/08 at 102),
5.88%, 1/20/38 1,000,000 (f) 977,590
State Health Facilities Authority
(Callable 5/15/12 at 100),
5.50%, 5/15/32 500,000 483,830
-------------
8,109,192
-------------
INDIANA (5.1%):
Health Facility Authority -- Columbus Hospital (FSA),
7.00%, 8/15/15 2,670,000 (b) 3,244,077
Municipal Bond Bank (Callable 2/1/04 at 102),
6.00%, 2/1/16 1,000,000 1,039,600
-------------
4,283,677
-------------
</Table>
SEE ACCOMPANYING NOTES TO SCHEDULE OF INVESTMENTS.
14
<Page>
<Table>
<Caption>
PRINCIPAL MARKET
DESCRIPTION OF SECURITY AMOUNT VALUE (a)
- ----------------------------------------------------------------- ------------- -------------
IOWA (3.7%):
Hospital Facilities Authority
(Callable 2/15/10 at 101),
6.75%, 2/15/15 $ 1,000,000 $ 1,093,220
Sheldon Health Care Facilities
(Callable 3/1/04 at 101),
6.15%, 3/1/16 1,000,000 1,031,490
State Higher Education Loan Authority (ACA)
(Callable 10/1/12 at 100),
5.50%, 10/1/33 1,000,000 (b) 1,001,340
-------------
3,126,050
-------------
KANSAS (1.3%):
Kansas City Utility Systems (FGIC)
(Callable 9/1/04 at 102),
6.25%, 9/1/14 1,000,000 (b) 1,066,000
-------------
KENTUCKY (3.6%):
State Housing Authority
(Callable 11/1/29 at 100),
6.08%, 1/1/30 3,000,000 3,076,980
-------------
MASSACHUSETTS (0.6%):
Boston Industrial Development Financing Authority, AMT
(Callable 9/1/12 at 102),
6.50%, 9/1/35 500,000 (f) 480,675
-------------
MICHIGAN (12.3%):
Comstock Park Public Schools (FGIC),
7.88%, 5/1/11 3,145,000 (b) 3,966,002
Hospital Financing Authority -- Daughters of Charity
(Escrowed to maturity, callable 11/1/05 at 101),
5.25%, 11/1/15 1,500,000 (c) 1,587,540
Kent Hospital Financial Authority (MBIA),
7.25%, 1/15/13 4,000,000 (b) 4,814,040
-------------
10,367,582
-------------
MINNESOTA (9.5%):
Eden Prairie Multifamily Housing (GNMA)
(Callable 1/20/08 at 102),
5.60%, 7/20/28 400,000 (b) 404,788
Fairview Health Care
(Callable 11/15/10 at 101),
6.38%, 11/15/29 1,000,000 1,058,200
</Table>
SEE ACCOMPANYING NOTES TO SCHEDULE OF INVESTMENTS.
15
<Page>
<Table>
<Caption>
PRINCIPAL MARKET
DESCRIPTION OF SECURITY AMOUNT VALUE (a)
- ----------------------------------------------------------------- ------------- -------------
Glencoe Health Care Facilities
(Callable 4/1/11 at 101),
7.50%, 4/1/31 $ 900,000 $ 910,953
Minneapolis and St. Paul Metropolitan Airport
Commission (FGIC)
(Callable 1/1/10 at 101),
5.75%, 1/1/32 1,000,000 (b) 1,038,610
Minneapolis Health Care System,
6.00%,11/15/23 565,000 586,154
Moorhead Golf Course
(Callable 12/1/08 at 100),
5.88%,12/1/21 2,490,000 2,520,403
State Agricultural and Economic Development Board
Revenue, Convertible, Zero-Coupon Bond
(Callable 11/15/10 at 101),
5.06%,11/15/22 2,290,000 (g) 1,513,232
-------------
8,032,340
-------------
MISSOURI (1.8%):
Cape Girardeau County Industrial Development Authority
(Callable 6/1/12 at 100),
5.75%, 6/1/32 500,000 501,330
St. Louis Industrial Development Authority
(Callable 12/15/10 at 102),
6.88%, 12/15/20 1,000,000 981,630
-------------
1,482,960
-------------
NEBRASKA (1.2%):
Douglas County School District
(Callable 6/15/11 at 100),
5.00%, 12/15/22 1,000,000 1,003,170
-------------
NEVADA (2.5%):
Washoe County School District (MBIA)
(Prerefunded to 6/1/04 at 101),
5.75%, 6/1/12 2,000,000 (b)(e) 2,099,420
-------------
NEW MEXICO (7.0%):
Mortgage Finance Authority,
6.88%, 1/1/25 2,410,000 2,594,220
Mortgage Finance Authority,
6.50%, 7/1/25 1,750,000 1,844,027
</Table>
SEE ACCOMPANYING NOTES TO SCHEDULE OF INVESTMENTS.
16
<Page>
<Table>
<Caption>
PRINCIPAL MARKET
DESCRIPTION OF SECURITY AMOUNT VALUE (a)
- ----------------------------------------------------------------- ------------- -------------
Mortgage Finance Authority,
6.75%, 7/1/25 $ 1,490,000 $ 1,509,534
-------------
5,947,781
-------------
NEW YORK (3.1%):
New York City, Series B,
5.75%, 8/1/16 1,400,000 1,463,994
New York Water and Sewer System
(Crossover refunded to 6/15/10 at 101),
6.00%, 6/15/33 380,000 (e) 431,209
New York Water and Sewer System
(Prerefunded to 6/15/10 at 101),
6.00%, 6/15/33 620,000 (e) 720,043
-------------
2,615,246
-------------
NORTH DAKOTA (3.3%):
Fargo Health Systems
(Callable 6/1/10 at 101),
5.63%, 6/1/31 1,750,000 1,778,088
Grand Forks Health Care Facilities (MBIA)
(Callable 3/24/03 at 101),
6.63%, 12/1/10 1,000,000 (b) 1,009,130
-------------
2,787,218
-------------
OHIO (2.5%):
Richland County Hospital Facilities
(Callable 11/15/10 at 101),
6.13%, 11/15/16 1,000,000 1,047,310
Richland County Hospital Facilities
(Callable 11/15/10 at 101),
6.38%, 11/15/30 1,000,000 1,037,830
-------------
2,085,140
-------------
SOUTH DAKOTA (3.2%):
Health and Education Facilities Authority -- Prairie Crossings
(Callable at 11/1/09 at 102),
6.00%, 11/1/19 2,000,000 2,133,020
Souix Falls Health Facilities
(Callable 11/15/12 at 100),
6.63%, 11/15/23 620,000 602,429
-------------
2,735,449
-------------
</Table>
SEE ACCOMPANYING NOTES TO SCHEDULE OF INVESTMENTS.
17
<Page>
<Table>
<Caption>
PRINCIPAL MARKET
DESCRIPTION OF SECURITY AMOUNT VALUE (a)
- ----------------------------------------------------------------- ------------- -------------
TENNESSEE (4.2%):
Johnson City Health and Education Facilities
(Callable 7/1/12 at 103),
7.50%, 7/1/33 $ 1,000,000 $ 1,069,540
Shelby County Health, Education and Housing Facilities
(Callable 9/1/12 at 100),
6.50%, 9/1/21 650,000 693,219
Sullivan County Health, Education and Housing Facilities
(Callable 9/1/12 at 101),
6.25%, 9/1/32 750,000 756,645
Sullivan County Health, Education and Housing
Facilities (RAAI) (Callable 9/1/13 at 100),
5.00%, 9/1/17 1,000,000 (b) 975,290
-------------
3,494,694
-------------
TEXAS (14.5%):
Abilene Health Facility Development Revenue
(Callable 5/15/09 at 101),
6.00%, 11/15/29 500,000 434,475
Abilene Health Facility Development Revenue
(Callable 8/15/08 at 101),
5.88%, 11/15/18 1,150,000 1,048,283
Arlington Independent School District
(Callable 2/15/05 at 100),
6.00%, 2/15/15 670,000 707,681
Brazoria County Environmental Authority
(Callable 5/15/12 at 100),
5.70%, 5/15/33 500,000 526,060
Brazos River Pollution Control Authority, AMT
(Callable 4/1/13 at 101),
7.70%, 4/1/33 500,000 (f) 550,875
Fort Bend Independent School District
(Escrowed to maturity),
5.00%, 2/15/14 1,000,000 (c) 1,071,070
Grand Prairie Independent School District (PSF)
(Callable 8/15/11 at 100),
5.85%, 2/15/26 40,000 (b) 42,491
Grand Prairie Independent School District (PSF)
(Prerefunded to 8/15/11 at 100),
5.85%, 2/15/26 2,960,000 (b) (e) 3,387,927
Gregg County Health Facilities Development Revenue
(Callable 10/1/12 at 100),
6.50%, 10/1/29 1,500,000 1,521,525
</Table>
SEE ACCOMPANYING NOTES TO SCHEDULE OF INVESTMENTS.
18
<Page>
<Table>
<Caption>
PRINCIPAL MARKET
DESCRIPTION OF SECURITY AMOUNT VALUE (a)
- ----------------------------------------------------------------- ------------- -------------
Houston Water Conveyance System (AMBAC),
7.50%, 12/15/16 $ 745,000 (b) $ 946,880
Sam Rayburn Municipal Power Agency (RAAI)
(Callable 10/1/12 at 100),
5.75%, 10/1/21 1,000,000 (b) 1,034,460
Tarrant County Housing and Finance Authority
(Callable 7/1/10 at 102),
6.88%, 7/1/30 585,000 519,065
Tyler Health Facility (Callable 7/1/13 at 100),
5.75%, 7/1/27 500,000 480,525
-------------
12,271,317
-------------
WASHINGTON (7.0%):
Chelan County Public Utility District, AMT (AMBAC)
(Callable 7/1/12 at 100),
5.25%, 7/1/37 2,500,000 (b) (f) 2,428,575
Douglas County Public Utility District (MBIA)
(Callable 1/1/05 at 102),
6.00%, 1/1/15 1,000,000 (b) 1,071,500
State Motor Vehicle Fuel Tax Revenue,
Zero-Coupon Bond (FGIC),
5.03%, 6/1/17 5,000,000 (b) (g) 2,424,950
-------------
5,925,025
-------------
WISCONSIN (4.9%):
State Health and Education Facility -- Beloit Hospital
(Callable 7/1/03 at 102),
5.90%, 7/1/11 625,000 636,156
State Health and Educational Facility Authority
(Callable 11/15/08 at 102),
5.75%, 11/15/27 1,800,000 1,495,170
State Health and Educational Facility Authority
(Callable 2/15/12 at 101),
5.75%, 8/15/30 1,500,000 1,516,410
State Health and Educational Facility Authority
(Callable 8/15/13 at 100),
6.00%, 11/15/23 500,000 491,945
-------------
4,139,681
-------------
Total Municipal Long-Term Securities
(cost: $113,238,074) 117,166,240
-------------
</Table>
SEE ACCOMPANYING NOTES TO SCHEDULE OF INVESTMENTS.
19
<Page>
<Table>
<Caption>
PRINCIPAL
AMOUNT/ MARKET
DESCRIPTION OF SECURITY SHARES VALUE (a)
- ----------------------------------------------------------------- ------------- -------------
MUNICIPAL SHORT-TERM SECURITIES (d) (1.8%):
IOWA (1.8%):
State Financial Authority,
0.90%, 2/1/23
(cost: $1,500,000) $ 1,500,000 $ 1,500,000
-------------
RELATED PARTY MONEY MARKET FUND (h) (12.4%):
First American Tax Free Obligations Fund
(cost: $10,469,763) 10,469,763 10,469,763
-------------
Total Investments in Securities (i) -- 153.0%
(cost: $125,207,837) $ 129,136,003
=============
</Table>
NOTES TO SCHEDULE OF INVESTMENTS:
(a) SECURITIES ARE VALUED IN ACCORDANCE WITH PROCEDURES DESCRIBED IN NOTE 2 TO
NOTES TO FINANCIAL STATEMENTS.
(b) PORTFOLIO ABBREVIATIONS AND DEFINITIONS:
ACA-AMERICAN CAPITAL ACCESS
AMBAC-AMERICAN MUNICIPAL BOND ASSURANCE COMPANY
FGIC-FINANCIAL GUARANTY INSURANCE CORPORATION
FSA-FINANCIAL SECURITY ASSURANCE
GNMA-GOVERNMENT NATIONAL MORTGAGE ASSOCIATION
MBIA-MUNICIPAL BOND INSURANCE ASSOCIATION
PSF-PERMANENT SCHOOL FUND
RAAI-RADIAN ASSET ASSURANCE, INC.
(c) ESCROWED TO MATURITY ISSUES ARE TYPICALLY BACKED BY U.S. GOVERNMENT
OBLIGATIONS. THESE BONDS MAY STILL BE SUBJECT TO CALL AT THE CALL DATE AND
PRICE INDICATED.
(d) FLOATING OR VARIABLE RATE OBLIGATION MATURING IN MORE THAN ONE YEAR. THE
INTEREST RATE, WHICH IS BASED ON SPECIFIC, OR AN INDEX OF, MARKET INTEREST
RATES, IS SUBJECT TO CHANGE PERIODICALLY AND IS THE EFFECTIVE RATE ON JULY
31, 2003. THIS INSTRUMENT MAY ALSO HAVE A DEMAND FEATURE WHICH ALLOWS THE
RECOVERY OF PRINCIPAL AT ANY TIME, OR AT SPECIFIED INTERVALS NOT EXCEEDING
ONE YEAR, ON UP TO 30 DAYS' NOTICE. MATURITY DATE SHOWN REPRESENTS FINAL
MATURITY.
(e) PREREFUNDED ISSUES ARE BACKED BY U.S. GOVERNMENT OBLIGATIONS. CROSSOVER
REFUNDED ISSUES ARE BACKED BY THE CREDIT OF THE REFUNDING ISSUER. IN BOTH
CASES THE BONDS MATURE AT THE DATE AND PRICE INDICATED.
(f) AMT-ALTERNATIVE MINIMUM TAX. AS OF JULY 31, 2003, THE AGGREGATE MARKET
VALUE OF SECURITIES SUBJECT TO THE ALTERNATIVE MINIMUM TAX IS $4,437,715,
WHICH REPRESENTS 3.5% OF NET ASSETS APPLICABLE TO COMMON SHARES.
(g) FOR ZERO-COUPON INVESTMENTS, THE INTEREST RATE SHOWN IS THE EFFECTIVE YIELD
ON THE DATE OF PURCHASE.
20
<Page>
(h) THIS MONEY MARKET FUND IS ADVISED BY U.S. BANCORP ASSET MANAGEMENT, INC.,
WHICH ALSO SERVES AS ADVISOR FOR THE FUND. SEE NOTE 5 IN NOTES TO FINANCIAL
STATEMENTS.
(i) ON JULY 31, 2003, THE COST OF INVESTMENTS IN SECURITIES FOR FEDERAL
INCOME TAX PURPOSES APPROXIMATED THE AMOUNT REPORTED FOR FINANCIAL
REPORTING PURPOSES. THE AGGREGATE GROSS UNREALIZED APPRECIATION AND
DEPRECIATION OF INVESTMENTS IN SECURITIES BASED ON THIS COST WERE AS
FOLLOWS:
<Table>
GROSS UNREALIZED APPRECIATION $ 5,832,828
GROSS UNREALIZED DEPRECIATION (1,904,659)
------------
NET UNREALIZED APPRECIATION $ 3,928,166
============
</Table>
21
<Page>
SHAREHOLDER UPDATE (Unaudited)
HOW TO OBTAIN A COPY OF THE FUND'S PROXY VOTING POLICIES A
description of the policies and procedures that the Fund
uses to determine how to vote proxies relating to portfolio
securities is available (1) without charge upon request by
calling 800.677.FUND; (2) at firstamericanfunds.com; and (3)
on the U.S. Securities and Exchange Commission's website at
sec.gov.
22
<Page>
BOARD OF DIRECTORS
VIRGINIA STRINGER
Chairperson of American Municipal Income Portfolio
Owner and President of Strategic Management Resources, Inc.
BENJAMIN FIELD III*
Senior Financial Advisor to, and formerly Senior Vice President, Chief Financial
Officer, and Treasurer of, Bemis Company, Inc.
MICKEY FORET*
Director of Minnesota Municipal Income Fund II
Consultant to, and formerly Executive Vice President and Chief Financial Officer
of, Northwest Airlines, Inc.
ROGER GIBSON
Director of American Municipal Income Portfolio
Vice President, Cargo-United Airlines
VICTORIA HERGET*
Director of American Municipal Income Portfolio
Investment Consultant; former Managing Director of Zurich Scudder Investments
LEONARD KEDROWSKI
Director of American Municipal Income Portfolio
Owner and President of Executive and Management Consulting, Inc.
RICHARD RIEDERER
Director of American Municipal Income Portfolio
Retired; former President and Chief Executive Officer of Weirton Steel
JOSEPH STRAUSS
Director of American Municipal Income Portfolio
Former Chairman of First American Investment Funds, Inc.
Owner and President of Strauss Management Company
JAMES WADE
Director of American Municipal Income Portfolio
Owner and President of Jim Wade Homes
*DID NOT SERVE AS DIRECTOR DURING THE PERIOD COVERED BY THIS REPORT.
<Page>
[FIRST AMERICAN(TM) LOGO]
AMERICAN MUNICIPAL INCOME PORTFOLIO
2003 SEMIANNUAL REPORT
U.S. Bancorp Asset Management, Inc., is a wholly owned subsidiary of U.S. Bank
National Association, which is a wholly owned subsidiary of U.S. Bancorp.
[RECYCLED SYMBOL]
This document is printed on paper containing 10% postconsumer waste.
9/2003 0168-03 XAA-SAR
<Page>
ITEM 2 - Code of Ethics
RESPONSE: Not applicable to semi-annual report
ITEM 3 - Audit Committee Financial Expert
RESPONSE: Not applicable to semi-annual report
ITEM 4 - Principal Accountant Fees and Services
RESPONSE: Not applicable to semi-annual report
ITEM 5 - Audit Committee of Listed Registrants
RESPONSE: Not applicable to semi-annual report
ITEM 6 - Reserved
ITEM 7 - Disclosure of Proxy Voting Policies and Procedures for Closed-End
Management Investment Companies
RESPONSE: Not applicable to semi-annual report
ITEM 8 - Reserved
ITEM 9 - Controls and Procedures
RESPONSE:
(a) The registrant's Principal Executive Officer and Principal Financial
Officer have evaluated the registrant's disclosure controls and procedures
within 90 days of the date of this filing and have concluded that the
registrant's disclosure controls and procedures were effective, as of that
date, in ensuring that information required to be disclosed by the
registrant in this Form N-CSR was recorded, processed, summarized and
reported timely. Notwithstanding this conclusion, the registrant's
Principal Executive Officer and Principal Financial Officer seek continuous
improvements to the registrant's disclosure controls and procedures.
(b) There were no changes in the registrant's internal control over financial
reporting that occurred during the registrant's most recent fiscal
half-year that have materially affected, or are reasonably likely to
materially affect, the registrant's internal control over financial
reporting.
ITEM 10 - EXHIBITS
10(a) - Code of Ethics
RESPONSE: Not applicable to semi-annual report
10(b) - Attach certifications (4 in total pursuant to Sections 302 and 906 for
PEO/PFO)
RESPONSE: Attached hereto
<Page>
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934 and the
Investment Company Act of 1940, the registrant has duly caused this report to be
signed on its behalf by the undersigned, thereunto duly authorized.
American Municipal Income Portfolio Inc.
By /s/ Thomas S. Schreier, Jr.
---------------------------
Thomas S. Schreier, Jr.
President
Date: September 30, 2003
Pursuant to the requirements of the Securities Exchange Act of 1934 and the
Investment Company Act of 1940, this report has been signed below by the
following persons on behalf of the registrant and in the capacities and on the
dates indicated.
By /s/ Thomas S. Schreier, Jr.
---------------------------
Thomas S. Schreier, Jr.
President
Date: September 30, 2003
By /s/ Robert H. Nelson
-----------------------
Robert H. Nelson
Treasurer
Date: September 30, 2003