Exhibit 11.4

ALLEGIANCE TELECOM, INC.        COMPUTATION OF PER SHARE LOSS        NINE MONTHS ENDED SEPTEMBER 30, 2001

|                                      |                                                     | Number of Shares |            | Percent Outstanding |        | Equivalent Shares |             
|------------------------------------- | --------------------------------------------------- | ---------------- | ---------- | ------------------- | ------ | ----------------- | ------------
|Prior to Initial Public Offering      |                                                     |                  |            |                     |        |                   |             
|                                      | 1997 Common Stock Offering                          |                  | 639        |                     | 100.00 | %                 |             
|After Initial Public Offering         |                                                     |                  |            |                     |        |                   |             
|                                      | 1998 Common Stock Offering                          |                  | 15,000,000 |                     | 100.00 | %                 |             
|                                      | Preferred Stock Converted to Common Stock           |                  | 60,511,692 |                     | 100.00 | %                 |             
|                                      | 1999 Common Stock Offering                          |                  | 21,041,100 |                     | 100.00 | %                 |             
|                                      | 2000 Common Stock Offering                          |                  | 10,703,109 |                     | 100.00 | %                 |             
|                                      | Cash in Lieu of Stock Split                         |                  | (577       | )                   | 100.00 | %                 |             
|                                      | Treasury Shares                                     |                  | (327,495   | )                   | 100.00 | %                 |             
|                                      | Warrants Exercised                                  |                  | 765,833    |                     | 100.00 | %                 |             
|                                      | Stock Options Exercised                             |                  | 1,228,039  |                     | 89.02  | %                 |             
|                                      | Employee Stock Discount Purchase Plan Shares Issued |                  | 548,211    |                     | 77.73  | %                 |             
|                                      | Common Stock Issued for Business Acquisitions       |                  | 5,084,545  |                     | 63.49  | %                 |             
|                                      |                                                     |                  |            |                     |        |                   |             
|WEIGHTED AVERAGE SHARES OUTSTANDING   |                                                     |                  |            |                     |        |                   | 112,441,562 
|NET LOSS APPLICABLE TO COMMON STOCK   |                                                     |                  |            |                     |        | $                 | (306,215,000
|                                      |                                                     |                  |            |                     |        |                   |             
|NET LOSS PER SHARE, BASIC AND DILUTED |                                                     |                  |            |                     |        | $                 | (2.72       
|                                      |                                                     |                  |            |                     |        |                   |             

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