The board of directors for the developer of master-planned communities called the $90-per-share offer from Pershing Square "not acceptable in its current form."

The board deemed Pershing Square Capital’s acquisition proposal “not acceptable in its current form,” and both sides signed a standstill agreement.

Investor Bill Ackman said shares of Howard Hughes Holding could fall into the low 60s if his proposal to buy stock in the real estate company and turn it into a modern-day Berkshire Hathaway is rejected.