Red Rock Island, the San Francisco Bay's only privately owned island, is now off the market, according to real estate site TheRealDeal.

Listing agent Chris Lim, who represents the firm Christie’s International Realty, confirmed to the publication that the island was indeed sold, but could not confirm who the mystery buyer is, citing a "lengthy" escrow process not expected to close until the end of next year, before adding that he is currently under a legally-binding NDA.

The island, which went up for sale last year for $25 million, was initially bought in 1964 for around $50,000 by local attorney David Glickman. Adjusted for inflation, that would be around $500,000 today. Glickman, whose interest lies in peculiar, idiosyncratic properties, told NPR in 2007 that he believed the island, "with some imagination could be made into something worthwhile.”

In a video promoting the listing, Lim noted that the island's signature dusty red-orange coloration arose as a result of Reconstruction-era mining of manganese used for paint pigments which were then-popular in Europe.

Brock Durning, an Alaskan resident who's selling the island to aid his ailing mother, inherited the land from his father Mack Durning, Glickman's business partner. How exactly the island found itself under the custody of the Durning family is still murky in its details.

Lim told KPIX that the change in ownership of the island resulted from Glickman losing a bet to the elder Durning on who would live longest. Mack Durning's ex-wife, Mona, has gone on the record saying that her late husband received fifty-percent ownership of the island when Glickman moved out of the area four decades ago, and that he made monthly payments for 18 years for the remaining ownership share.

TheRealDeal was unable to verify these claims in their reporting.

The island, which has changed hands multiple times since the 1800s, has seen multiple proposals for development over the years, all of which have fallen through - not helped in part, by the island's remote and jurisdictionally complex location, found itself suddenly all the rage when it first when up for sale last year.

Lim said the level of interest by suitors from across the world was, "reflective of the island being the only private island in the San Francisco Bay."

Or in other words, Lim says that each prospective patron agreed with the assessment of the island expressed in the aforementioned promotional video.

“This is a once in a lifetime chance to indulge in the ultimate island fantasy,” he said in the video.

Previously: San Francisco's Only Private Island, Red Rock, Hits the Market Again

Photo: Red Rock Island, a private island in San Francisco Bay, is visible in an aerial view, Sausalito, California, April 2, 2023. (Photo by Smith Collection/Gado/Getty Images)