There is growing discontent among shareholders over Macerich’s decision last month to reject Simon Property Group’s offer to acquire the mall owner and developer for $16.8 billion, or $95.50 a share.

Macerich’s fourth-biggest shareholder, Cohen & Steers, on Wednesday asked the mall owner and developer to come up with a plan that would deliver as much value as Simon’s attempted takeover.

On Thursday, shareholders Land & Buildings and Orange County revealed that they had formed an investment group to advocate for change at Macerich. Two letters sent to Art Coppola, chairman and chief executive officer of Macerich, and a press release issued publicly by the new entity, Orange/L&B, claims that Macerich tried to block the nominations of two of its candidates to the Macerich board. The letter also highlights “the egregious governance missteps undertaken by Macerich in relation to their refusal to meaningfully engage with Simon Property Group.” Orange/L&B said it will now pursue litigation through the courts for the right to nominate four highly qualified directors to the board of Macerich.

In the letter, signed by Jonathan Litt, founder and chief information officer of Land & Buildings, the poison pill adopted by the Macerich board is criticized. “Although poison pills are not uncommon, Macerich’s poison pill is unusually onerous.” The poison pill prevents Simon or anyone from acquiring more than a 10 percent stake in Macerich. “Of all the poison pills currently in effect, only 10 percent have a 10 percent threshold like the Macerich poison pill.”

Litt also objected to the classification of Macerich’s board, where directors are assigned to one of three classes, each serving three-year terms, a move solely intended to protect stockholder value. Macerich has said the board’s classification isn’t permanent.

The letter urges Coppola to put three new directors on the board and reengage with Simon “given the fact that your own valuation shows that you are only approximately 5 percent apart. The opportunity still exists for you to abide by your fiduciary duties for the benefit of your shareholders.”