1 EXHIBIT 99.a MASCO CORPORATION AND CONSOLIDATED SUBSIDIARIES COMPUTATION OF PRIMARY AND FULLY DILUTED PER SHARE EARNINGS (INCLUDING EFFECT OF FULL DILUTION) 1993 1992 1991 -------- -------- -------- (IN THOUSANDS EXCEPT AS INDICATED) Shares for computation of primary and fully diluted earnings per share: Average number of shares outstanding........................ 152,700 151,700 149,900 Common stock equivalents: Convertible debentures................................... 4,210 4,210 4,210 Stock options............................................ 1,520 1,210 700 -------- -------- -------- Total shares........................................... 158,430 157,120 154,810 -------- -------- -------- -------- -------- -------- Net income.................................................... $221,100 $183,100 $ 44,900 Addback of debenture interest, net............................ 5,880 5,970 5,970 -------- -------- -------- Net income, as adjusted....................................... $226,980 $189,070 $ 50,870 -------- -------- -------- -------- -------- -------- Primary and fully diluted earnings per share (in dollar amounts).................................................... $1.45 $1.21 $.30 ----- ----- ---- ----- ----- ---- The above dilutive influences are less than 3%.