A Merrill Lynch analyst ate a handful of magic mushrooms in his Manhattan apartment on Sunday—and then plunged to his death out of his 26th floor window, sources said.

Alex Lagowitz, 23, landed on a third floor, outdoor patio around 10 a.m. — straight down from his bedroom at Windsor Court on East 31st Street and Lexington Avenue in Murray Hill, according to police.

Authorities believe his death was a suicide, though they did not elaborate.

“He was really high on mushrooms,” a police source said, explaining that Lagowitz had “jumped out the window.”

Sources said that Lagowitz, who is from Livingston, NJ, and was a star golfer on the Colgate University team, took four grams of the drug — which is enough to cause hallucinations.

“When you take these mushrooms, they make you hallucinate and, in some cases, if you take enough of them, they make you believe that you can fly like Superman,” a police narcotics source explained. “Only problem is Superman is really a mirage.”

Lagowitz and his roommate, Max Kaplan, 22, had ingested the mushrooms earlier in the day, sources said.

Kaplan — a George Washington University grad from West Orange, NJ — told cops he fell asleep a short time later, and when he woke up, Lagowitz was nowhere to be found.

It wasn’t until police arrived at their apartment to investigate hours later that the scatterbrained young man came to and realized what had happened.

“He was stunned,” a source said. “He had no idea that his friend had taken a swan dive.”

Kaplan was charged with criminal possession of a controlled substance for the remaining mushrooms found inside the apartment, which is said to be housed in “a very post college building.”

“[Windsor Court] is filled with young people who have too much money and too much time on their hands,” explained a dad who was visiting his son after he recently moved in.

Dean Chenarides, a 28-year-old resident who lives in the building, agreed — saying it “definitely has a night life.”

“You have a sub group from our generation who are in their 20s and early 30s and they have money and like to party sometimes,” he said. “Those parties get out of control. I’ll step out of the elevator and the smell of marijuana will hit you right in the face.”

Lagowitz, a credit trading analyst at Bank of America Merrill Lynch since June 2015, can be seen in Facebook pictures gnawing on cigars and taking golfing trips with his father. He recently went to the Super Bowl in February with his dad.

“Alex truly was a great, warm guy who could always put a smile on his friend’s faces,” said a fellow Colgate graduate, who asked to remain

anonymous out of respect for the family.

Lagowitz’ mother refused to comment when reached by phone Monday.

Additional reporting by Priscilla DeGregory