The major iBuyers sold approximately 20 percent of their inventory directly to investors in 2021, more than double the previous high in 2019.

Why it matters: These sales -- a growing part of the iBuyer business model -- mainly occur off market, meaning traditional home buyers never see them. And most of them are subsequently turned into rental properties.

By the numbers: This amounts to nearly 8,000 sales in 2021, a relatively small number, but one that has quadrupled since 2019.

• Even though the number is small, it still matters -- especially to the thousands of families that missed out on the opportunity of homeownership.

All three of the major iBuyers sold significant portions of their inventory to institutional investors in 2021, with Opendoor leading the pack.

The big picture: Investors bought a record number of homes in 2021, and not just from iBuyers.

• "Last year, investors bought nearly one in seven homes sold in America’s top metropolitan areas, the most in at least two decades," according to a Washington Post analysis.
  

• "Those purchases come at a time when would-be buyers across the country are seeing wildly escalating prices, raising the question of what impact investors are having on prices for everyone else."

Fast forward: Opendoor's IPO documents set a goal of buying and selling upwards of 140,000 houses a year. Selling 20 percent to investors amounts to nearly 30,000 houses each year.

• Taking inventory off the market, turning them into rentals, and reducing home ownership opportunities aren't part of the iBuyer narrative, but that's what's happening.
  

• Selling to investors may be a sound business decision, but there are real world implications that directly affect thousands of American families.