(Reuters) - Simon Property Group Inc (>> Simon Property Group Inc), the No.1 U.S. mall owner, made what it said was its "best and final offer" for Macerich Co (>> Macerich Co) three days after its smaller rival rejected its initial proposal and adopted a poison pill takeover defense.

Simon Property raised its cash-and-stock offer for Macerich on Friday to $95.50 per share from $91.00, and said it would withdraw the offer, valued at $23.2 billion, if Macerich did not meet with the company by April 1.

Macerich shares fell 8 percent in early trading, suggesting that investors doubt the deal would go through, given the company's strong defensive actions this week, including a change in its board structure.

"I guess people are saying Macerich won't bite," Sandler O'Neill & Partners analyst Alexander Goldfarb said. "Macerich's history has been very independent and marching to their own beat and I don't know if this is enough to compel them."

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.

"The 'this is the best and final offer' wording is never going to be viewed favorably by the market," SunTrust Robinson Humphrey analyst Ki Bin Kim said.

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.

Macerich had said the earlier offer "undervalued" the company. Simon Property, however, has maintained that its offer was higher than the $71 per share deal that Macerich struck with Ontario Teachers' Pension Plan in November for a sale of 10.9 percent stake in return for full ownership of a joint venture.

Macerich said on Thursday that the November deal was not representative of its value.

"We believe this type of 'apples and oranges' comparison is just a tactic Simon is employing as part of its effort to force the sale of Macerich at the lowest possible price," Macerich told Reuters.

Macerich shares were down 7.2 percent at $86.80, giving up nearly all the gains made since March 6, a day before Simon Property made its first offer.

(Additional reporting by Rohit T.K. in Bengaluru; Editing by Kirti Pandey)

By Sagarika Jaisinghani and Herbert Lash

Stocks treated in this article : Macerich Co, Simon Property Group Inc