Bill Ackman bought an apartment for $90 million and he's pretty sure it's a steal

Billionaire hedge fund manager Bill Ackman dropped $91.5 million on a luxury One57 apartment last month, together with a group of investors.

It's the second-most expensive apartment sale in New York City - ever - but Ackman says he bought it "at a very attractive price."

Speaking at the 2015 Sohn Conference on Monday, he told Bloomberg's Stephanie Ruhle that the apartment is an "investment."

"I think it's the best apartment in the world," said Ackman, who does not intend to ever live there.

The six-bedroom, 13,554-square foot unit is located on the 75th and 76th floors of the swanky One57 condo, reports The Real Deal.

Ackman told Ruhle he thinks he got the place cheap because apartments overlooking New York's Central Park usually go for $10,000 per square foot. At $91.5 million, he only paid $6,750 per square foot.

Initially, Ackman said he bought the apartment "for fun." Now it sounds like he's changing his tone. He said he lives in a normal "family" apartment.