When the housing market tanked in 2007, investors were quick on the scene with cash to buy distressed and foreclosed properties at deeply discounted prices. Private equity fund Blackstone was said to pump $1 billion in 2012 alone into single family homes. Other private equity goliaths did likewise. Hundreds of millions - probably billions - more has been invested by small investment groups, some focused on single family homes, others on multi-family housing. Going on ten years after the crash, the question now is: when will these investors cash in their real estate holdings and put that money to work in traditional vehicles such as stocks and bonds?

The answer just may be: not now, maybe not ever. At least some experts and investors argue that many investors look to stay put in real estate.

The reasons are two-fold. For one, in much of the country, real estate continues to appreciate. Secondly, rents continue to climb. The Apartment List rental report, for instance, showed a 2.7% jump in rents from May 2015 to May 2016 and, year in, year out, rents in most markets have risen.

"Investors who bought up foreclosures in the wake of the Great Recession have no incentive to sell yet, with the rental market performing so well," said real estate investor Brian Davis, who owns 15 properties. "Until we start hearing talk of a bubble, I don't foresee investors unloading properties en masse."

He added: "Stocks have been a volatile mess, while housing markets continue to appreciate and rents continue to rise."

That is the fact: income property, in much of the country, continues to reward the patience of investor-owners. And traditional equity markets this year have been characterized by tumult, as investors chew on worries about oil prices, the Chinese economy, the possible United Kingdom exit from the European Union, Europe's refugee problems and more.

Housing has its issues. Liquidity is not always high and that means the investment cannot be counted on to become instant cash, as generally is the case with stocks. But, aside from that, many investors seem content with what they perceive as the advantages of housing.

"In our metropolitan area, and many around the country, rents have continued to escalate," said Michael Vraa, a lawyer in Minneapolis. "Some investors seemed like good bets to get out of the landlord game a couple of years ago, but stuck it out, because they realized they could keep raising the rent. Not many investments allow you to increase your income by a steady 10% to 20% each year, but in the last four or five years, many landlords have done just that."

"Since 2009, I was able to turn a small $20-30,000 investment into nearly half a million in value," Eric Bowlin, a real estate investor in Worcester County, Mass. "My real estate provides more stable returns than the stock market."  He added: "My income is protected from downswings because the rental market is inversely related to housing prices -- more foreclosures cause prices to go down and rents to go up."

Will it last?

"Currently we see investors staying with rental properties for the foreseeable future, as there's still plenty of deals out there," said Arcadia, Calif. Realtor Brian LeBow.

Realtor Mark Ferguson points to two especially big pluses for investment property: "Tax advantages are huge: being able to depreciate real estate is a huge tax advantage not available with stocks."

His other plus: "Financing: You can finance rentals, which allows control over a much larger asset than your investment. If you invest wisely, this can increase returns and all the benefits listed above."

A savvy investor still can convert $100,000 in cash into ownership of a $500,000 apartment building in much of the country, and get rents from multiple tenants as well as depreciation allowances that can become big tax savings.  That's a powerful formula that is wooing many to stay put in real estate.

Will there be another real estate bubble, and when will it burst? Experts agree that another bubble will come - that has been a cyclical reality in US real estate. But nobody sees it in the near-term horizon. A very few markets - possibly San Francisco, maybe Manhattan - are fingered by some as edging into bust bubble status. But most of the U.S. real estate market appears to be steady as she goes and very probably the same will be true for today's real estate investors.

This article is commentary by an independent contributor.