Chicago's tallest building could soon be named after a billionaire's private equity firm

Next, the Willis Tower could become the Blackstone Tower.

Steve Schwarzman's private equity fund is buying the Willis Tower, it announced Monday. At 110 stories, the Willis Tower bills itself as the fifth-tallest office building in the world (for a time, the Willis Tower also went as the Sears Tower).

Blackstone Real Estate Partners VII, a property investment fund that is totally separate from Blackstone's flagship private equity investment vehicles, is making the acquisition, although terms were not publicized. However, a report in Crain's had suggested a price tag of $1.5 billion for the deal.

Blackstone has a recent history of striking big deals for iconic properties. Right before the financial crisis hit, Blackstone did its biggest deal in the form of a $26 billion deal for Hilton Hotels in 2007. Last year, Hilton was brought back onto public markets by Blackstone, in a successful IPO, and as the private equity firm has reduced its share in Hilton the hotelier has also struck deals of its own, including the $1.95 billion sale of New York City's Waldorf Astoria hotel to Anbang Insurance Group Co., a Chinese firm.

So far in 2015, Blackstone CEO Schwarzman has had a good year. His 2014 pay, announced last month at $690 million, far eclipsed his 2013 tally of less than $500 million.