As your question implies, not many. In fact, whenever the Cosmopolitan Casino Resort opens, it will have the distinction of being a casino that changed ownership while still under construction. (Deutsche Bank is in the process of foreclosing upon developer Ian Bruce Eichner.)
MGM Grand is something of a curate’s egg, too, as it was built around the preexisting Marina Hotel, which Kirk Kerkorian bought and incorporated into what we now know as the MGM Grand. If you're ever visiting the Grand and happen to be staying in the West Wing rooms, you are actually in the old Marina.
On the Strip, the casinos still in the hands of their original owners tend to be of relatively recent vintage: the Venetian (1999) and its sequel, The Palazzo (2007), as well as Wynn Las Vegas (2005).
Boyd Gaming’s California Hotel downtown, which opened in 1975, has never changed hands, nor has the same company’s Sam’s Town, which opened four years later. Just off the Strip, Ellis Island Casino & Brewery appears to have remained in the Ellis family’s hand for the last 20 years. A few hole-in-the-wall casinos might also qualify, but it’s difficult to tell from property records.
The build-to-own champ at present is Station Casinos, which turned a bingo hall into Palace Station, following that in due course with Boulder Station, Texas Station, Sunset Station, Green Valley Ranch, and Red Rock Resort. Although Cannery Casino Resorts is in the process of being sold to Crown Ltd., it still maintains ownership of its signature property in North Las Vegas and is building an even grander one on Boulder Highway.
Then there’s the curious case of South Point, née South Coast, which Boyd Gaming inherited as part of its absorption of Coast Resorts in 2004. It underperformed right out of the gate and apparently became something of a bone of contention between Coast CEO Michael Gaughan and his new bosses at Boyd. Eventually, to smooth things out and save face all around, Boyd agreed to swap Gaughan’s stake in the company. In return, Gaughan got to take South Coast/Point with him, thereby becoming one of the few Vegas casino operators –- if not the only one –- to sell and then repurchase his original casino.
