Exhibit 11.1 AMERICAN MOBILE SATELLITE CORPORATION ------------------------------------- COMPUTATIONS OF EARNING PER COMMON SHARE ---------------------------------------- (in thousands, except per share amounts) Three Months Six Months Ended Ended June 30, June 30, 1996 1995 1996 1995 ------------ ---------- ------------ ---------- PRIMARY CALCULATION - ------------------- Net Loss $(43,509) $(8,133) $(73,386) $(14,462) ========= ======== ========= ======== Net Loss per common share $(1.72) $(.33) $(2.94) $(.58) ========= ======== ========= ======== Weighted-average common shares outstanding 25,286 24,899 25,003 24,854 ========= ======== ========= ======== FULLY DILUTED CALCULATION - ------------------------- Net Loss (1) $(40,024) $(8,133) $(67,992) $(14,462) ========= ======== ========= ======== Net Loss per common share $(1.57) $(.33) $(2.69) $(.58) ========= ======== ========= ======== Weighted-average common shares outstanding (2) 25,429 24,955 25,258 24,895 ========= ======== ========= ======== (1) Calculated as follows: Three Months Six Months Ended Ended June 30, June 30, 1996 1995 1996 1995 ------------ ---------- ------------ ---------- Primary net loss $(43,509) $(8,133) $(73,386) $(14,462) Amortization of debt discount 1,258 -- 2,253 -- Interest on convertible debt 2,227 -- 3,141 -- --------- -------- --------- -------- $(40,024) $(8,133) $(67,992) $(14,462) ========= ======== ========= ======== (2) Calculated as follows: Historical weighted average number of shares outstanding 25,286 24,899 25,003 24,854 Assumed exercise of stock options 43 56 108 41 Assumed exercise of stock purchase warrants 100 -- 147 -- ------- -------- ------- -------- 25,429 24,955 25,258 24,895 ======== ======== ======== ======== 13