Former Yahoo! CEO Terry Semel -- Unloads Malibu Estate for $13 Million Under Asking Price

Terry Semel -- the former CEO of Yahoo! -- really, really, really wanted to sell off his giant Malibu estate ... so much so, he was willing to knock $13 MILLION off the asking price, TMZ has learned.

Back in May, Semel wanted a cool $50 mil for his 10,000 square-foot, beach front ... but TMZ has learned the house just went into escrow after Terry accepted an offer for a mere $37,000,000.

It's unclear how much Semel originally paid for the glass palace ... but he's probably not shedding too many tears over the $13 Million price slash -- since he made close to $500 MILLION during his stint at Yahoo!

So what do you get for $37 Million these days -- 9 bedrooms, 13.5 baths ... 151 feet of beach frontage ... a 3-story rotunda ... giant outdoor pool ... jacuzzi ... gazebo ... guest house ... gym and a screening room.