Shares of Blackstone Inc. and other housing-related companies tumbled after President Donald Trump said he would move to ban institutional investors from buying single-family homes. 

Blackstone stock fell by as much as 9.3%, before trimming some losses, after Trump said he was "immediately taking steps to ban large institutional investors from buying more single-family homes," the latest push toward housing affordability. Blackstone is a major investor in residential real estate.

"This should have a material impact on their business. PE firms are having a tough time monetizing many of their investments," said Matt Maley, chief market strategist at Miller Tabak + Co LLC. "But, Blackstone has generated some nice income running the largest single-family rental business in the US. So, it's not a surprise that the recent rebound in the stock has seen a larger reversal today."

Other notable decliners included home rental company American Homes 4 Rent, dropping 11%, while Invitation Homes Inc. declined 10% and homebuilding materials company Builders FirstSource Inc. fell over 5%. The S&P 1500 Homebuilding Index slid as much as 2.2%, with 15 of 18 members trading lower. 

Trump made the announcement Wednesday on social media, and said he would ask Congress to codify the action, but did not immediately provide details on what his effort would entail. Trump said he would discuss the topic — alongside other cost-of-living initiatives — during a speech at the World Economic Forum in Davos later this month.