NEW YORK - GAF Corp. stepped up its effort to take over Union Carbide Corp. on Thursday with a new cash offer of $74 a share for the 90 percent of Carbide's stock it does not already own, or a total of about $4.5 billion.
The bid was $6 higher than its last offer, which encompassed 48 million shares, or 71.3 percent of Union Carbide's outstanding shares.
Union Carbide, which has been opposing GAF's takeover attempt, offered last week to buy back 35 percent of its shares for $85 each - $20 in cash and $65 in securities. However, analysts have said the market might value the securities at less than $65.
In a letter to Warren Anderson, chairman and chief …