Shares of Howard Hughes Holdings jumped after hedge-fund manager Bill Ackman's firm offered to buy 11.8 million Howard Hughes shares at $85 apiece to own a majority stake in the company. The stock jumped about 9.

Ackman proposed a takeover of real estate developer Howard Hughes for $85 a share and said he is displeased with its recent stock performance.

Billionaire hedge fund manager Bill Ackman announced plans to build a modern-day Berkshire Hathaway ( BRK.A 1.68%) ( BRK.B 1.79%). Although Ackman and his investors would own most of it, it would be available to invest in as a publicly traded company.