President Trump said he wants to ban institutional investors from buying up more single-family homes, a policy that has rare bipartisan support in Congress and broad popular appeal.

“People live in homes, not corporations,” Trump posted on Truth Social on Wednesday. The announcement sent shares of private equity giant Blackstone, which has amassed a broad rental home portfolio, and rental specialists like Invitation Homes and American Homes 4 Rent sharply lower.

The only problem? Experts don’t think it will make a major difference in the affordability crisis.

Policies that encourage building, particularly dense housing in sought-after neighborhoods, are more likely to help improve affordability than banning institutional landlords, said Daryl Fairweather, chief economist at Redfin.

Learn more: Housing market predictions: What buyers, renters, and homeowners can expect

“The reason housing has gotten so unaffordable is because there is a shortage of homes,” Fairweather said. “It’s the shortage of homes that makes investors want to buy the homes because they see that there’s scarcity.”

Giant landlords — typically defined as those who own over 1,000 homes — have been under fire since the aftermath of the financial crisis, when they began buying up homes at beaten-down prices, fixing them up, and renting them out. Critics say their actions push up rents and home prices by reducing the supply of homes that would otherwise go to owner-occupants and that many corporate landlords are quick to evict but slow to provide basic maintenance.

But for all their purchases — the largest companies own around 80,000 homes — institutions make up only a tiny fraction of the US housing market. They own around 3.4% of all rental homes, and landlords with 100 or more homes make less than 1% of all purchases, according to housing consultancy John Burns Research and Consulting.