Land & Buildings Investment Management, which has roughly a 3% stake in theme-park operator Six Flags Entertainment Corp., wants that company to sell or otherwise monetize its real estate holdings, according to a presentation posted by the activist investor on Wednesday.

In the presentation, Land & Buildings calls Six Flags "a thrilling real estate opportunity," asserting that the company could add $11 per share by unlocking its real estate value.

Six Flags owns and operates 27 theme and water parks in North America. Land & Buildings estimates that its real estate is more valuable than Six Flags' entire current market cap of about $1.8B.

As of Wednesday, Six Flags stock traded at about $23.40, up more than 11% for the day. Compared with a year ago, however, its stock is down about 45%.

Under prior leadership several years ago, Six Flags explored monetizing its real estate by creating a REIT structure, but decided against it at the time, The Wall Street Journal reports.

Land & Buildings even suggested a possible buyer for Six Flags' real estate, namely entertainment giant Vici Properties, which it says has "expressed a strong interest in acquiring real estate related to theme parks," and moreover has the capital to do so.

Other potentially interested parties include Gaming and Leisure Properties, Realty Income, EPR Properties, Blackstone Mortgage Trust and various private equity funds, according to Land & Buildings.

"It is the ideal time to take action to monetize Six Flags’ uniquely valuable real estate portfolio, given the high multiples similar assets are trading at in the public and private markets," Land & Buildings Chief Investment Officer Jonathan Litt said in a statement.

Some Six Flags properties have sold off individually through the years. The Denver Six Flags, also called Elitch Gardens, was purchased by Florida-based CNL Properties in 2007, and in 2015 sold to a Denver-based investment group that includes retail and entertainment billionaire Stan Kroenke.

Kroenke's ownership group, which also includes Revesco Properties, has since kicked off a redevelopment effort at Elitch Gardens, which sits on 62 acres just outside Denver's central business district. The decades-long project, dubbed River Mile, could effectively double the size of downtown Denver when it is complete.

This isn't the first rodeo for Land & Buildings when it comes to urging entertainment specialists to separate from their real estate for the sweet reward of shareholder value creation.

In 2015, the investor pushed MGM Resorts International to create a REIT for its real estate. Eventually, MGM did so for some of its holdings, forming MGM Growth Properties. This summer, Vici acquired the REIT in a deal valuing the company at $17.2B.