EXHIBIT 11 INTERRA FINANCIAL AND SUBSIDIARIES COMPUTATION OF NET EARNINGS PER SHARE (UNAUDITED, IN THOUSANDS, EXCEPT PER-SHARE AMOUNTS) THREE MONTHS ENDED NINE MONTHS ENDED SEPTEMBER 30, SEPTEMBER 30, ---------------------- ------------------------- 1997 1996 1997 1996 -------- --------- ---------- ---------- Primary earnings per share: Net earnings. . . . . . . . . . . . . . . . . . . . . $ 7,056 $ 12,990 $ 33,948 $ 41,098 -------- --------- --------- --------- -------- --------- --------- --------- Average number of common and common equivalent shares outstanding: Average common shares outstanding . . . . . . . . . . 12,294 12,155 12,260 12,121 Stock options . . . . . . . . . . . . . . . . . . . . 718 511 707 453 Shares credited to deferred compensation Plan participants. . . . . . . . . . . . . . . . . 214 111 199 92 -------- --------- --------- --------- 13,226 12,777 13,166 12,666 -------- --------- --------- --------- -------- --------- --------- --------- Primary earnings per share . . . . . . . . . . . . . . . $ .53 $ 1.02 $ 2.58 $ 3.24 -------- --------- --------- --------- -------- --------- --------- --------- Earnings per share assuming full dilution: Net earnings. . . . . . . . . . . . . . . . . . . . . $ 7,056 $ 12,990 $ 33,948 $ 41,098 -------- --------- --------- --------- -------- --------- --------- --------- Average number of common and common equivalent shares outstanding: Average common shares outstanding . . . . . . . . . . 12,294 12,155 12,260 12,121 Stock options . . . . . . . . . . . . . . . . . . . . 892 654 921 676 Shares credited to deferred compensation Plan participants. . . . . . . . . . . . . . . . . 214 111 199 92 -------- --------- --------- --------- 13,400 12,920 13,380 12,889 -------- --------- --------- --------- -------- --------- --------- --------- Fully diluted earnings per share . . . . . . . . . . . . $ .53 $ 1.01 $ 2.54 $ 3.19 -------- --------- --------- --------- -------- --------- --------- --------- 15