EXHIBIT 11 CAPSTEAD MORTGAGE CORPORATION AND SUBSIDIARIES COMPUTATION OF EARNINGS PER SHARE (IN THOUSANDS, EXCEPT PER SHARE AMOUNTS) QUARTER ENDED NINE MONTHS ENDED SEPTEMBER 30 SEPTEMBER 30 -------------------------- ------------------------- 1997 1996 1997 1996 ----------- ------------- ----------- ------------ PRIMARY: Average number of common shares outstanding 52,765 38,319 49,431 36,872 Incremental shares calculated using the Treasury Stock method 1,190 883 1,109 856 ------- ------- -------- -------- 53,955 39,202 50,540 37,728 ======= ======= ======== ======== Net income $41,867 $32,428 $118,926 $ 91,429 Less cash dividends paid on convertible preferred stock: Series A ($0.40 per share) (166) (195) (519) (616) Series B ($0.315 per share) (5,907) (8,643) (19,415) (27,909) ------- ------- -------- -------- Net income available to common stockholders $35,794 $23,590 $ 98,992 $ 62,904 ======= ======= ======== ======== Primary net income per share $0.66 $0.60 $1.96 $1.67 ======= ======= ======== ======== FULLY DILUTED: Average number of common shares outstanding 52,765 38,319 49,431 36,872 Assumed conversion of convertible preferred stock: Series A 865 1,032 904 1,070 Series B 14,208 21,514 15,431 22,016 Incremental shares calculated using the Treasury Stock method 1,190 892 1,214 1,173 ------- ------- -------- -------- 69,028 61,757 66,980 61,131 ======= ======= ======== ======== Net income available to common stockholders $41,867 $32,428 $118,926 $ 91,429 ======= ======= ======== ======== Fully diluted net income per share $0.61 $0.53 $1.78 $1.50 ======= ======= ======== ========