In a sign of just how soft the market’s become for luxury co-ops, the owner of a duplex at 740 Park Avenue is now offering his apartment for $22.5 million — nearly 25 percent off the original asking price.

The 7,500-square-foot unit, located at one of the Upper East Side’s most prestigious addresses, is priced at $3,000 per square foot following the price chop. The five-bedroom apartment first hit the market in 2013, when it was listed at $29.5 million. With no takers, the unit was pulled off the market, only to return in 2015 asking $27.5 million.

The pad is owned by investor Peter Huang, who purchased it in the 1970s, according to Michael Gross’ book, “740 Park: The Story of the World’s Richest Apartment Building.”

Located on the fourth and fifth floors of the tony Rosario Candela-designed building, the apartment has 41 windows with north, south and west exposures. It features an eat-in chef’s kitchen, library and three wood-burning fireplaces. The master suite is accessible via an original marble staircase. Compass’ Kyle Blackmon has the listing.

One of the city’s marquee apartment buildings — whose famous residents have included Jacqueline Kennedy Onassis and John D. Rockefeller — is now home to designer Vera Wang, Blackstone’s Stephen Schwarzman and billionaire David Koch. In 2014, hedge funder Israel Englander bought an 18-room apartment at 740 Park for $71.3 million.

But the market’s changed a lot since then. Co-op sales above $4 million dropped 26 percent year-over-year in 2016, according to a recent analysis by the Wall Street Journal.

740 Park also hit a rough patch last year amid a flagging luxury market, when its limestone facade began to crumble.  And a fire that tore through a sixth-floor apartment caused extensive damage to apartments owned by Koch and hedge funder David Ganek, who owns Jackie O’s old home. Unrelated to the damage, Ganek — who listed the apartment for $44 million in 2014 — has also cut the asking price of the unit to $29.5 million.