He’s not doing much “whooping” now.

A Manhattan hedge-fund manager whose loud grunting and cheering during an Upper East Side spin class allegedly led a fed-up broker on the bike nearby to nearly break his neck is furious that prosecutors aren’t treating the assault as a felony.

“This wasn’t just a playground fall where Stewy fell down and went boo hoo,” angry victim Stuart Sugarman said when told that his alleged attacker was charged yesterday with a mere misdemeanor.

“The reality is I spent two weeks in Lenox Hill [Hospital], including a week in ICU and six hours in surgery,” Sugarman complained. “My life has been altered, possibly permanently. This is not a misdemeanor.”

Sugarman, 48, a fund manager and investment banker at Sunrise Financial Group, admits that he noisily war-whooped, groaned and shouted, “You go, girl!” during his last spin workout Aug. 15 at an Equinox gym on East 85th Street. That, he says, didn’t give broker Christopher Carter, who was three bikes over, the right to repeatedly yell, “Shut the f- – – up!” and then leap off his Schwinn and come charging at him.

The grunting Sugarman is accusing the allegedly berserk broker – both men top 200 pounds – of tilting Sugarman’s stationary bike’s front wheel up a yard off the floor and flipping the bike and Sugarman into a wall.

Sugarman suffered a concussion from the bike’s falling on top of him, along with damage to six discs in the vertebrae of his neck. His surgeon, he said, tells him he was “one click away from a wheelchair.”

“The guy had a spinal-cord contusion with major surgery to his neck involving the use of cadaver tissue and multiple metal plates and screws,” said Sugarman’s lawyer, Samuel Davis.

The criminal complaint lodged yesterday against Carter, 44, of Maxim Investments Group, only accuses him of causing “sustained lower-back pain” and “substantial pain” but makes no mention of the serious physical injury needed to characterize an assault as a felony.

Prosecutors declined to comment on the case. Carter’s lawyer, Michael Farkas, said only that his client “did not commit any criminal acts.”

“Mr. Sugarman is clearly taking advantage of the criminal-justice system to build some civil lawsuit,” he said. Sugarman has yet to file a suit.

laura.italiano@nypost.com