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                                 UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549
                            ------------------------

                                  FORM 10-K/A

(MARK ONE)

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   /X/     ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
           SECURITIES EXCHANGE ACT OF 1934
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                  FOR THE FISCAL YEAR ENDED DECEMBER 31, 2001
                                       OR

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   / /     TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
           SECURITIES EXCHANGE ACT OF 1934
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        FOR THE TRANSITION PERIOD FROM ______________ TO ______________

                          COMMISSION FILE NO. 1-15371
                           --------------------------

                              ISTAR FINANCIAL INC.

             (Exact name of registrant as specified in its charter)

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                    MARYLAND                                         95-6881527
        (State or other jurisdiction of                           (I.R.S. Employer
         incorporation or organization)                        Identification Number)

    1114 AVENUE OF THE AMERICAS, 27TH FLOOR                            10036
               NEW YORK, NY 10036                                    (Zip code)
    (Address of principal executive offices)
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       Registrant's telephone number, including area code: (212) 930-9400
                            ------------------------

          Securities registered pursuant to Section 12(b) of the Act:

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             Title of each class:                     Name of Exchange on which registered:

        COMMON STOCK, $0.001 PAR VALUE                       NEW YORK STOCK EXCHANGE

     9.375% SERIES B CUMULATIVE REDEEMABLE                   NEW YORK STOCK EXCHANGE
       PREFERRED STOCK, $0.001 PAR VALUE

     9.200% SERIES C CUMULATIVE REDEEMABLE                   NEW YORK STOCK EXCHANGE
       PREFERRED STOCK, $0.001 PAR VALUE

     8.000% SERIES D CUMULATIVE REDEEMABLE                   NEW YORK STOCK EXCHANGE
       PREFERRED STOCK, $0.001 PAR VALUE
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        Securities registered pursuant to Section 12(g) of the Act: None

    Indicate by check mark whether the registrant: (i) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports); and (ii) has been subject to such
filing requirements for the past 90 days. Yes /X/ No / /

    Indicate by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K is not contained herein, and will not be contained, to the
best of registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K. / /

    As of March 15, 2002, the aggregate market value of the common stock, $0.001
par value per share of iStar Financial Inc. ("Common Stock"), held by
non-affiliates(1) of the registrant was approximately $2.4 billion, based upon
the closing price of $28.29 on the New York Stock Exchange composite tape on
such date.

    As of March 15, 2002, there were 87,877,976 shares of Common Stock
outstanding.

(1) For purposes of this Annual Report only, includes all outstanding Common
    Stock other than Common Stock held directly by the Registrant's directors
    and executive officers.

                      DOCUMENTS INCORPORATED BY REFERENCE

1.  Portions of the registrant's definitive proxy statement for the registrant's
    2002 Annual Meeting, to be filed within 120 days after the close of the
    registrant's fiscal year, are incorporated by reference into Part III of
    this Annual Report on Form 10-K.

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ITEM 6. SELECTED FINANCIAL DATA

    The following table sets forth selected financial data on a consolidated
historical basis for the Company. However, prior to March 1998, as discussed
more fully in Note 1 to the Company's Consolidated Financial Statements (the
"Recapitalization Transactions"), the Company did not have substantial
operations or capital resources. Prior to the Recapitalization Transactions, the
Company's structured finance operations were conducted by two private investment
partnerships which contributed substantially all their structured finance assets
to the Company in the Recapitalization Transactions in exchange for cash and
shares of the Company.

    Further, on November 4, 1999, as more fully discussed in Note 4 to the
Company's Consolidated Financial Statements, the Company acquired TriNet, which
increased the size of the Company's operations, and also acquired its external
advisor. Operating results for the year ended December 31, 1999 reflect only the
effects of these transactions subsequent to their consummation.

    Accordingly, the historical balance sheet information as of and prior to
December 31, 1998, as well as the results of operations for the Company for all
periods prior to and including the year ended December 31, 1999, do not reflect
the current operations of the Company as a well capitalized, internally-managed
finance company operating in the commercial real estate industry. For these
reasons, the Company believes that the information contained in the following
tables relating to the 1997 period is not indicative of the Company's current
business and should be read in conjunction with the discussions set forth in
Item 7--"Management's Discussion and Analysis of Financial Condition and Results
of Operations."

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<Caption>
                                                                         FOR THE YEAR ENDED DECEMBER 31,
                                                          -------------------------------------------------------------
                                                             2001         2000         1999         1998         1997
                                                          ----------   ----------   ----------   -----------   --------
                                                                                                
OPERATING DATA:
Interest income.........................................  $  254,119   $  268,011   $  209,848   $   112,914   $   896
Operating lease income..................................     201,257      185,956       42,186        12,378        --
Other income............................................      28,800       17,855       12,763         2,804       991
                                                          ----------   ----------   ----------   -----------   -------
    Total revenue.......................................     484,176      471,822      264,797       128,096     1,887
                                                          ----------   ----------   ----------   -----------   -------
Interest expense........................................     170,121      173,891       91,184        44,697        --
Operating costs-corporate tenant lease assets...........      12,800       12,809        2,246            --        --
Depreciation and amortization...........................      35,642       34,514       10,340         4,287        --
General and administrative..............................      24,151       25,706        6,269         2,583       461
General and administrative--
  Stock-based compensation..............................       3,575        2,864          412         5,985        --
Provision for loan losses...............................       7,000        6,500        4,750         2,750        --
Advisory fees...........................................          --           --       16,193         7,837        --
Costs incurred in acquiring external advisor(1).........          --           --       94,476            --        --
                                                          ----------   ----------   ----------   -----------   -------
    Total expenses......................................     253,289      256,284      225,870        68,139       461
                                                          ----------   ----------   ----------   -----------   -------
Income before minority interest, gain on sales of
  corporate tenant lease assets, extraordinary loss and
  cumulative effect of change in accounting principle...     230,887      215,538       38,927        59,957     1,426
Minority interest in consolidated entities..............        (218)        (195)         (41)          (54)   (1,415)
Gain on sales of corporate tenant lease assets..........       1,145        2,948           --            --        --
Extraordinary loss on early extinguishment of debt......      (1,620)        (705)          --            --        --
Cumulative effect of change in accounting
  principle(2)..........................................        (282)          --           --            --        --
                                                          ----------   ----------   ----------   -----------   -------
Net income..............................................  $  229,912   $  217,586   $   38,886   $    59,903   $    11
Preferred dividend requirements.........................     (36,908)     (36,908)     (23,843)         (944)       --
                                                          ----------   ----------   ----------   -----------   -------
Net income allocable to common shareholders.............  $  193,004   $  180,678   $   15,043   $    58,959   $    11
                                                          ==========   ==========   ==========   ===========   =======
Basic earnings per common share(3)......................  $     2.24   $     2.11   $     0.25   $      1.40   $  0.01
                                                          ==========   ==========   ==========   ===========   =======
Diluted earnings per common share.......................  $     2.19   $     2.10   $     0.25   $      1.36   $  0.00
                                                          ==========   ==========   ==========   ===========   =======
Dividends declared per common share(4)..................  $     2.45   $     2.40   $     1.86   $      1.14   $  0.00
                                                          ==========   ==========   ==========   ===========   =======
</Table>

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<Table>
<Caption>
                                                                         FOR THE YEAR ENDED DECEMBER 31,
                                                          -------------------------------------------------------------
                                                             2001         2000         1999         1998         1997
                                                          ----------   ----------   ----------   -----------   --------
                                                                                                
SUPPLEMENTAL DATA:
Dividends declared on preferred shares..................  $   36,578   $   36,576   $   24,819   $       929   $    --
Dividends declared on common shares.....................     213,089      205,477      116,813        60,343        --
Adjusted earnings allocable to common
  shareholders(5)(7)....................................     255,132      230,688      127,798        66,615        11
Cash flows from:
  Operating activities..................................  $  264,835   $  202,715   $  119,625   $    54,915   $ 1,271
  Investing activities..................................    (321,100)    (176,652)    (143,911)   (1,271,309)   (6,013)
  Financing activities..................................      49,183      (37,719)      48,584     1,226,208     4,924
EBITDA(6)(7)............................................     436,650      423,943      140,451       116,778        --
Ratio of EBITDA to interest expense(8)..................       2.57x        2.44x        1.54x         2.44x        --
Ratio of EBITDA to combined fixed charges(9)............       2.10x        2.01x        1.22x         2.39x        --
Ratio of earnings to fixed charges(10)..................        2.3x         2.2x         1.4x          2.3x        --
Ratio of earnings to fixed charges and preferred stock
  dividends(10).........................................        1.9x         1.9x         1.1x          2.3x        --
Weighted average common shares outstanding--basic(11)...      86,349       85,441       57,749        41,607     1,258
Weighted average common shares
  outstanding--diluted(11)..............................      88,234       86,151       60,393        43,460     2,562

BALANCE SHEET DATA:
Loans and other lending investments, net................  $2,377,763   $2,225,183   $2,003,506   $ 1,823,761   $    --
Corporate tenant lease assets, net......................   1,841,800    1,670,169    1,714,284       189,942        --
Total assets............................................   4,378,560    4,034,775    3,813,552     2,059,616    13,441
Debt obligations........................................   2,495,369    2,131,967    1,901,204     1,055,719        --
Minority interest in consolidated entities..............       2,650        6,224        2,565            --     5,175
Shareholders' equity....................................   1,787,778    1,787,885    1,801,343       970,728     6,351

SUPPLEMENTAL DATA:
Total debt to shareholders' equity......................        1.4x         1.2x         1.1x          1.1x        --
</Table>

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EXPLANATORY NOTES:
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(1) As more fully discussed in Note 4 to the Company's Consolidated Financial
    Statements, this amount represents a non-recurring, non-cash charge of
    approximately $94.5 million relating to the acquisition of the Company's
    external advisor in November 1999.

(2) Represents one-time effect of adoption of Statement of Financial Accounting
    Standards No. 133, "Accounting for Derivative Instruments and Hedging
    Activities" as of January 1, 2001.

(3) Prior to November 1999, earnings per common share excludes 1% of net income
    allocable to the Company's former class B shares. The former class B shares
    were exchanged for Common Stock in connection with the acquisition of TriNet
    and other related transactions on November 4, 1999. As a result, the Company
    now has a single class of Common Stock outstanding.

(4) The Company generally declares common and preferred dividends in the month
    subsequent to the end of the quarter.

(5) Adjusted earnings represents net income in accordance with GAAP, before
    gains (losses) on sales of corporate tenant lease assets, extraordinary
    items and cumulative effect of change in accounting principle, plus
    depreciation and amortization, less preferred stock dividends, and after
    adjustments for unconsolidated partnerships and joint ventures and, for the
    year ended December 31, 1999, exclude the non-recurring, non-cash cost
    incurred in acquiring the Company's external advisor (see Note 4 to the
    Company's Consolidated Financial Statements).

(6) EBITDA is calculated as total revenue minus the sum of general and
    administrative expenses, general and administrative--stock-based
    compensation, provision for loan losses and operating costs on corporate
    tenant lease assets.

(7) Each of adjusted earnings and EBITDA should be examined in conjunction with
    net income as shown in the Consolidated Statements of Operations. Neither
    adjusted earnings nor EBITDA should be considered as an alternative to net
    income (determined in accordance with GAAP) as an indicator of the Company's
    performance, or to cash flows from operating activities (determined in
    accordance with GAAP) as a measure of the Company's liquidity, nor is either
    measure indicative of funds available to fund the Company's cash needs or
    available for distribution to shareholders. The Company's management
    believes that adjusted earnings and EBITDA more closely approximate
    operating cash flow and are useful measures for investors to consider, in
    conjunction with net income and other GAAP measures, in evaluating the
    Company's financial performance. This is primarily because the Company is a
    commercial finance company that focuses on real estate lending and corporate
    tenant leasing; therefore, the Company's net income (determined in
    accordance with GAAP) reflects significant non-cash depreciation expense on
    corporate tenant lease assets. It should be noted that the Company's manner
    of calculating adjusted earnings and EBITDA may differ from the calculations
    of similarly-titled measures by other companies.

(8) The 1999 and 1998 EBITDA to interest expense ratios on a pro forma basis
    (see Note 4 to the Company's Conslidated Financial Statements) would have
    been 2.83x and 2.84x, respectively.

(9) Combined fixed charges are comprised of interest expense, capitalized
    interest, amortization of loan costs and preferred stock dividend
    requirements. The 1999 and 1998 EBITDA to combined fixed charges ratios on a
    pro forma basis (see Note 4 to the Company's Conslidated Financial
    Statements) would have been 2.23x and 2.44x, respectively.

(10) For the purposes of calculating the ratio of earnings to fixed charges,
    "earnings" consist of income from continuing operations before income taxes
    and cumulative effect of changes in accounting principles plus "fixed
    charges" and certain other adjustments. "Fixed charges" consist of interest
    incurred on all indebtedness related to continuing operations (including
    amortization of original issue discount) and the implied interest component
    of the Company's rent obligations in the years presented. For 1999, these
    ratios include the effect of a non-recurring, non-cash charge in the amount
    of approximately $94.5 million relating to the November 1999 acquisition of
    the former external advisor to the Company. Excluding the effect of this
    non-recurring, non-cash charge, the ratio of earnings to fixed charges for
    that period would have been 2.5x and our ratio of earnings to fixed charges
    and preferred stock dividends would have been 2.0x.

(11) As adjusted for one-for-six reverse stock split effected by the Company on
    June 19, 1998.

                                       4
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                                   SIGNATURES

    Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, as amended, and Rule 12b-15 of that Act, the Registrant
has duly caused this Amendment to be signed on its behalf by the undersigned,
thereunto duly authorized.

<Table>
                                                   
                                                      iSTAR FINANCIAL INC.
                                                      REGISTRANT

Date: July 18, 2002                                   /s/ JAY SUGARMAN
                                                      ------------------------------------------------
                                                      Jay Sugarman
                                                      CHAIRMAN OF THE BOARD OF DIRECTORS

                                                      /s/ SPENCER B. HABER
                                                      ------------------------------------------------
                                                      Spencer B. Haber
                                                      PRESIDENT, CHIEF FINANCIAL OFFICER AND DIRECTOR
</Table>

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