Miami Beach mansion he's been trying to sell for about seven months now.
Of course, that's only about 5 percent off the original $20 million asking price. And he can make it back in about seven seconds, if you believe reports about his TV-commercial earnings.
The home is on celebrity-rich North Bay Road, where stars like Jennifer Lopez and A-Rod have lived. The double lot has 170 feet of water frontage on Biscayne Bay -- Damon and his wife combined neighboring properties -- adding up to a 1-acre compound that the listing agency calls "by far one of the largest in the region." (No, we're not sure either how it can "by far" be merely one of the largest.)
The main estate was built in 1935. Living space totals 12,705 square feet, comprising a "palatial mansion" with five bedrooms and eight bathrooms as well as a two-bedroom, two-bath guesthouse. The home offers views of the bay and downtown Miami -- "all for the reasonable price of $20,000,000." (Yes, that's a real quote! A few days after the real estate agents published the blog post that we're quoting, the price came down by a million and change, so we're guessing it wasn't quite reasonable enough.)
As we recently wrote here on Yahoo Homes' blog, Damon and his family bought a house in Southern California last year just down the street from Ben Affleck. To see a slideshow of that Pacific Palisades home, click here.
We'll also take this opportunity to highlight a genuinely worthy cause of Damon's: He co-founded water.org, dedicated to solving the shocking water and sanitation problems in much of the world.
More people in the world have a cell phone than have a toilet, water.org says. In fact, 2.5 billion people lack access to a toilet.
"I was so just shocked by this," Damon told CNN. "The toilet? Yeah, there's the guest room toilet, the toilet in your [bedroom] -- you know, there are toilets everywhere. How can this be?"
For the record: The Miami Beach estate has a total of 10 bathrooms, as does the Pacific Palisades home.
Related on Yahoo Homes:
• Matt Damon's L.A. compound down the street from buddy Ben Affleck
• The sad, little-known story of the house Jackie designed for JFK -- the only home they built
• Sammy Sosa hits a homer with new Miami mansion