A few months ago, Stuart Leaf was sitting in his Brooklyn Heights apartment when he got a call from his wife asking when he’d be home. It turned out “we’d both been home for three hours,” he said—their roughly 11,000-square-foot condo is so large that neither one realized the other was there.

After that, it was clear to the couple that it was time to sell, especially since they are about to become empty-nesters. The apartment is “just a little bit too spread out” for just for the two of them, said Mr. Leaf, the 53-year-old founder of Cadogan Management, a fund of hedge funds that merged with Cantor Fitzgerald in 2011.

Now listing for $32 million with Karen and Alan Heyman of Sotheby’s International Realty, the unit is the priciest condo ever to hit the market in Brooklyn, Ms. Heyman said. (The borough’s most expensive home for sale is a roughly 17,500-square-foot townhouse listed for $40 million.) If Mr. Leaf’s apartment fetches its asking price, it would be by far the highest-price condo sale in the borough. The current condo record is held by a unit at the Clock Tower in Dumbo, which sold for $7 million in 2008, according to Ms. Heyman.

The unit originally hit the market in May, but went off the market in February because the couple wasn’t sure where they wanted to move, Mr. Leaf said. Now that they “have a pretty good idea” where they’re headed next, he said, it is relisting at the same price.