1 EXHIBIT 11 CABOT CORPORATION Earnings per Common Share for the Year Ended September 30, 1997 Statement Re: Computation of Per Share Earnings (In thousands, except per share amounts) Primary Fully Diluted ------- ------------- Shares of common stock outstanding at October 1, 1996, less treasury stock 71,589 71,589 Plus net weighted shares of treasury stock purchased (1,714) (1,714) Plus common stock equivalents: Effect of convertible preferred stock conversion - 5,981 Effect of equity incentive awards 855 880 ------- ------- Weighted average shares outstanding 70,730 76,736 ======= ======= Income applicable to common shares $89,487 $89,487 Dividends on preferred stock - 3,258 Preferred stock conversion compensation shortfall - (1,798) ------- ------- Earnings applicable to common shares $89,487 $90,947 ======= ======= Earnings per common share $ 1.27 $ 1.19 ======= =======