1 EXHIBIT 12.1 XO COMMUNICATIONS RATIO OF EARNINGS TO FIXED CHARGES (IN THOUSANDS) ----------------------------------------------------------------------- FOR THE YEAR ENDED FOR THE NINE MONTHS ----------------------------------------------------------------------- ENDED 1995 1996 1997 1998 1999 SEPTEMBER 30, 2000 ------------- ------------ ------------ -------------- ------------ -------------------- EARNINGS: Net loss applicable to common shareholders $ (12,731) $ (71,101) $ (129,004) $ (278,340) $ (558,692) $ (609,736) Less interest capitalized during the period, net - - (1,793) (4,311) (9,924) (19,646) Add equity investment losses - 1,100 2,891 3,677 4,385 2,755 Add fixed charges 609 31,348 57,694 152,313 299,671 354,008 ------------- ------------ ------------ -------------- ------------ -------------------- CALCULATED EARNINGS $ (12,122) $ (38,653) $ (70,212) $ (126,661) $ (264,560) $ (272,619) FIXED CHARGES: Total interest expense including capitalized interest $ 499 $ 30,876 $ 56,288 $ 148,876 $ 293,047 $ 344,203 Est. of Interest within Rental Exp. 110 472 1,406 3,437 6,624 9,805 ------------- ------------ ------------ -------------- ------------ -------------------- TOTAL FIXED CHARGES $ 609 $ 31,348 $ 57,694 $ 152,313 $ 299,671 $ 354,008 RATIO OF EARNINGS TO FIXED CHARGES - - - - - - DEFICIENCY $ (12,731) $ (70,001) $ (127,906) $ (278,974) $ (564,231) $ (626,627)