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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, DC 20549

FORM 10-K/A
Amendment No. 1 to Form 10-K

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ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

FOR THE FISCAL YEAR ENDED DECEMBER 31, 2001

OR

o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

FOR THE TRANSITION PERIOD FROM                              TO                             .

COMMISSION FILE NUMBER: 0-24509

ALLEGIANCE TELECOM, INC.
(Exact Name of Registrant as Specified in its Charter)

DELAWARE (State of Incorporation)	75-2721491 (IRS Employer Identification No.)
9201 NORTH CENTRAL EXPRESSWAY DALLAS, TEXAS (Address of Principal Executive Offices)	75231 (Zip Code)

(214) 261-7100
Registrant's Telephone Number, Including Area Code

NONE
Securities Registered Pursuant to Section 12(b) of the Act

COMMON STOCK, PAR VALUE $.01, QUOTED ON THE NASDAQ NATIONAL MARKET
Securities Registered Pursuant to Section 12(g) of the Act

        Indicate by check mark whether Allegiance Telecom (1) 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 it was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ý    No o

        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 Allegiance Telecom'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. ý

        Based on the closing sales price on the Nasdaq National Market on March 27, 2002 of $3.12, the aggregate market value of our voting stock held by non-affiliates on such date was approximately $259.8 million. Shares of common stock held by directors and by each person who owns or may be deemed to own 10% or more of our outstanding common stock have been excluded, since such persons may be deemed to be affiliates. This determination of affiliate status is not necessarily a conclusive determination for other purposes. As of March 27, 2002, Allegiance Telecom, Inc. had 116,023,655 shares of common stock issued and outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

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Portions of Allegiance Telecom's definitive proxy statement for the annual meeting of stockholders for the fiscal year ended December 31, 2001, which will be filed with the SEC by April 30, 2002, are incorporated by reference into Part III of this Form 10-K.

EXPLANATORY NOTE

        The sole purpose of this Amendment No. 1 to Form 10-K is to add the following paragraphs before Part I of the Form 10-K filed on April 1, 2002:

FORWARD-LOOKING STATEMENTS

        This report contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995, and we intend that such forward-looking statements be subject to the safe harbors created by this law. You generally can identify these statements by our use of forward-looking words such as "plans," "estimates," "believes," "expects," "may," "will," "should" or "anticipates" or the negative or other variations of such terms or comparable terminology, or by discussion of strategy that involve risks and uncertainties. We often use these types of statements when discussing our plans and strategies, our anticipation of revenues from designated markets, and statements regarding the development of our businesses, the markets for our services and products, our anticipated capital expenditures, operations support systems or changes in regulatory requirements and other statements contained in this report regarding matters that are not historical facts.

        We caution you that these forward-looking statements are only predictions and estimates regarding future events and circumstances. We cannot assure you that we will achieve the future results reflected in these statements. The risks we face that could cause us not to achieve these results include, but are not limited to, the risks discussed in this report as well as our ability to do the following in a timely manner, at reasonable costs and on satisfactory terms and conditions:

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successfully market our services to current and new customers;



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attract and retain our customers;



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interconnect with and develop cooperative working relationships with incumbent local carriers;



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develop efficient operations support systems and other back office systems (including, but not limited to, provisioning and billing);



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successfully and efficiently transfer new customers to our networks;



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identify, finance, complete and integrate suitable acquisitions;



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borrow under our credit facilities or borrow under alternative financing sources;



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install new switching facilities and other network equipment;



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electronically interface with incumbent local carriers; and



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obtain leased fiber optic line capacity, rights-of-way, building access rights and any required governmental authorizations, franchises and permits.

        Regulatory, legislative and judicial developments could also cause actual results to differ materially from the future results reflected in such forward-looking statements. You should consider all of our subsequent written and oral forward-looking statements only in light of such cautionary statements. You should not place undue reliance on these forward-looking statements and you should understand that they represent management's view only as of the dates we make them.

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SIGNATURES

        Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, Allegiance Telecom, Inc. has duly caused this Amendment No. 1 to Form 10-K to be signed on its behalf by the undersigned, thereunto duly authorized on April 9, 2002.

ALLEGIANCE TELECOM, INC.
By:	/s/  MARK B. TRESNOWSKI Mark B. Tresnowski, Senior Vice President, General Counsel and Secretary

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DOCUMENTS INCORPORATED BY REFERENCE
EXPLANATORY NOTE
FORWARD-LOOKING STATEMENTS
SIGNATURES