Simon Property, the No.1 U.S. mall owner, raised its offer for Macerich three days after its smaller rival rejected its earlier offer, adopted a poison pill and changed board structure to prevent a hostile takeover.
Simon Property raised on Friday its cash-and-stock offer for Macerich to $95.50 per share from $91.00.
Simon Property said its offer, which has an enterprise value of $23.2 billion, would be withdrawn if Macerich did not meet with the company by April 1.
Macerich shares fell 10 percent to $84.10 in premarket trading.
The new offer values Macerich at $15.10 billion, based on 158.16 million shares outstanding as of Feb. 20.
Simon Property said it would not nominate directors to Macerich's board "or otherwise prolong this process."
The company said all other terms of its offer were unchanged, including a ratio of 50 percent in cash and 50 percent in Simon Property common stock.
Macerich could not be immediately reached for comment.
Simon Property had disclosed a 3.6 percent stake in Macerich in November, seen by many at the time as a precursor to a bid.