Would your mall be impacted by this potential deal?

Simon Property Group isn't going down without a fight.

On Friday, the largest U.S. real estate investment trust sweetened its offer to acquire fellow mall operator Macerich, in what it called its "best and final offer."

Simon's $100 billion portfolio of malls vastly outnumbers the 51 regional shopping malls and handful of power shopping centers owned by Macerich. However, a merger "makes sense given the limited geographic overlap between the portfolios and the potential synergies Simon could extract from Macerich," according to a recent note by Green Street Advisors.

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According to the real estate research firm, 45 percent of Macerich's net operating income comes from Arizona and California. Florida and Texas are the two states that account for the highest amount of net operating income for Simon.

Simon on Friday upped its offer to acquire all outstanding shares of Macerich for $95.50 in cash and Simon shares, up from its initial offer of $91 per share. The company said it will withdraw its offer if Macerich does not meet with Simon for negotiations by April 1.

Earlier this week, Macerich's board unanimously rejected Simon's offer, saying that it "substantially undervalues Macerich and is not in the best interests" of the company or its shareholders.

In November, Simon disclosed a 3.6 percent investment in Macerich.