Only about 1 in 4 former homeowners who lost property during the housing crash will soon become buyers again as tight credit keeps many out of the U.S. real estate market, according to a National Association of Realtors study.

Of the 9.3 million owners who went through foreclosure or were forced to sell at a loss, about 950,000 already have bought again, and 1.5 million more are likely to make a purchase in the next five years, the trade group said.

“They won’t be a significant factor to the housing market going forward,” Lawrence Yun, chief economist at the National Association of Realtors, said. “The majority of the 9.3 million won’t be coming back.”

The U.S. homeownership rate fell to 64 percent at the end of last year, a two-decade low and down from a high of 69.2 percent in 2004, according to Census Bureau data. The ownership rate will drop to 63.5 percent by 2016 and plateau for years, according to a report by Goldman Sachs analysts led by Hui Shan.

The 9.3 million homeowners the Realtors group studied gave up their homes through more than 5 million foreclosures and 4 million other distressed transactions since early 2007, including short sales and deeds in lieu of foreclosure, Yun said.

The estimate that 950,000 buyers have returned to date is based on surveys showing they accounted for about 7 percent of existing-home sales since 2012, when those who lost property to foreclosure became eligible again for Federal Housing Administration financing, Yun said.

California, Florida and Arizona, which had the highest numbers of foreclosures early in the housing crisis, will see the biggest share of return buyers over the next five years, Yun said. Many who have repaired their credit and hope to purchase again will face challenges in areas where home prices have recovered and affordability is out of reach, such as coastal California, he said.

From 2009 to 2013, tight credit stymied about 4 million potential homeowners, including both first-time buyers and so-called boomerang buyers who are coming back from losing property during the crash, according to a report issued last month by the Urban Institute.

While strict mortgage underwriting is keeping many from re-entering the market, the loose lending that fueled the housing bubble and ensuing crash enabled unqualified people to become owners, Yun said.

“Many of them should not have gotten a mortgage to begin with,” he said.