Macerich Co. rejected a $14.39 billion takeover offer from larger rival Simon Property Group Inc. said the proposal “substantially undervalues” the firm. Macerich is adopting a shareholder rights plan, with a 10% trigger and reorganized its board structure to stop a hostile takeover. Macerich, which received a $91 per share offer earlier in March, saw its shares fall 5% to $90.29 in early trading. The proposal was valued at $22.4 billion. Simon Property Chief Executive David Simon said, “Macerich’s rejection is based on a rosy view of its future prospects.”