(NewsNation) — The last year has been a nightmare for many Americans trying to buy a home. Historically low mortgage rates drove up demand, further tightening an already limited supply and bidding wars became the new normal.

Those who were able to find a place often lost out to all-cash offers, leading many to wonder: Who has that kind of money? Institutional investors became a common answer.

So how much are large, corporate investors to blame for rising home prices?

In June, a Democrat-led House subcommittee released new findings based on survey data collected from the five largest owners and operators of single-family rental homes in the United States. The committee staff found:

• Between March 2018 and September 2021, the five companies grew their inventory by 27%, or 76,235 single-family rental homes in total.
• They tended to purchase homes in neighborhoods with significantly higher Black populations than the national average.
• The companies tended to sell homes primarily through bulk sales (61.5% of the time) to other institutional investors and very rarely sold homes to their tenants (0.5% of the time).

The subcommittee also found that renters in institutionally-owned single-family rental homes may face additional challenges, such as higher rent increases, inflated fees and diminishing quality of housing over time.

Other analyses have also shown a spike in investor-purchased homes in recent years.

Real estate brokerage Redfin found investors bought a record 18.4% of all homes sold in the United States in the fourth quarter of 2021, up from 12.6% in the fourth quarter the year before.

That means investors bought roughly 80,000 homes in the last quarter of 2021. As recently as 2011, that number was below 20,000. Although it’s worth noting Redfin’s analysis was not limited to large corporate investors.

The percentage of homes bought by investors is much higher in some places, particularly across the sunbelt.

In Charlotte and Atlanta, investors accounted for more than 30% of purchased homes in the fourth quarter of 2021, Redfin determined.

In some cases, local governments are pushing back, purchasing homes to protect their housing inventory from institutional investors. In Cincinnati, where rental asking prices have skyrocketed more than 30% since last year, the Port of Greater Cincinnati Development Authority bought nearly 200 single-family homes that it intends to rent at more affordable prices.

But despite the recent buying activity, evidence suggests large corporate investors are not the main reason home prices have surged.

“The growth of institutional investors is a symptom, rather than the cause of extremely tight housing markets,” Jenny Schuetz, an urban economist at the Brookings Institute, told the house subcommittee in a hearing last week.

A recent analysis by Freddie Mac found large corporate investors still account for only 2.5% of home purchases nationwide. Whereas other investor segments, like individual investors, account for 24% of the market — a rate the report says has remained relatively flat since 2000.

“Although investors are certainly contributing to the affordable housing shortage, they are not the driver of the tight supply of homes available for purchase,” the report concluded.

Instead, Freddie Mac attributed the recent rise in home prices to four factors: record low mortgage rates in 2020 and 2021; limited supply from underbuilding; an increase in first-time home buyers due to age demographics; and increased migration from high-cost cities to areas that were already struggling with housing shortages.

During last week’s hearing, House Republicans accused Democrats of using institutional investors as scapegoats in order to distract from what they say are the primary drivers of rising home costs — policies that have disincentivized home builders and surging inflation.

“We cannot demonize institutions for facilitating this supply of quality housing (single-family rental units) that otherwise would be out of the realm of possibility for many Americans due to the economic consequences of inflation,” said Rep. Tom Emmer, R-Minn.

A 2021 analysis by the National Realtors Association found growth in America’s housing inventory has slowed significantly since the turn of the century. The report determined the U.S. had an “underbuilding gap” of as many as 6.8 million housing units since 2001.

That supply problem, Schuetz said, has been driven by local governments passing policies that make it difficult to build more homes in desirable areas. She pointed to common zoning rules that limit the construction of small, moderately priced homes as an example.

This challenge is made more difficult because the same housing policies constraining supply are politically popular with existing homeowners, Schuetz noted.

“This is a long-term problem caused fundamentally by the fact that we’re not building enough homes,” said Schuetz.