EXHIBIT 11(A) VIALOG CORPORATION CALCULATION OF SHARES USED IN DETERMINING NET LOSS PER SHARE (Unaudited) Three Months Ended Six Months Ended June 30, June 30, -------------------- -------------------- 1999 2000 1999 2000 --------- --------- --------- --------- Common stock, beginning of period........................... 8,399,066 9,137,854 3,693,672 9,133,569 Weighted average common shares issued during period, net........ 163,183 235,372 3,446,474 137,559 Common stock options and warrants using the treasury stock method.. -- -- -- -- --------- --------- --------- --------- 8,562,249 9,373,226 7,140,146 9,271,128 ========= ========= ========= ========= Net loss (in thousands)........... $ (5,208) $ (1,087) $ (6,925) $ (2,278) ========= ========= ========= ========= Basic and diluted net loss per share............................ $ (0.61) $ (0.12) $ (0.97) $ (0.25) ========= ========= ========= ========= 20