Funds boss Bill Ackman is getting a pile of cash — and the last laugh at rivals who pooh-poohed his bet on now-bankrupt mall giant General Growth Properties.

The firm’s prized malls around the US drew a surprise $10 billion bankruptcy bid yesterday from its chief competitor, Simon Property Group. The nation’s No. 1 mall owner wants to cherry-pick the crown jewels from General Growth, its runner-up. General’s assets here include South Street Seaport and the Staten Island Mall.

General shot up 28 percent to $12.02, a sign that traders expect a higher bid from Simon.

General Growth called Simon’s bid too low and said it would seek other bids.

Pundits piled on immediately, recalling that Ackman got slammed just two months ago by rival fund Hovde Capital in a report entitled “Fools Gold” that trashed Ackman’s bankruptcy consolidation bet.

Ackman, who recently said General has up to $43 a share in unlocked value, didn’t return calls for comment.

Simon’s unsolicited cash bid would give shareholders $9 a share, including $6 in cash. Unsecured creditors would get 100 cents on the dollar, or about $7 billion.

Simon’s stock rose 4 percent to $74.82, up $2.82.