Flickr / Rhys A. Real estate investing is all about timing, and Sam Zell knows this better than anyone.

He sold his real estate firm, Equity Office, to Blackstone Group for $39 billion near the peak of the market. This was back in February 2007—only months before real estate credit markets started to spiral out of control.

He’s doing it again.

At the end of October, his real estate fund, Equity Residential, agreed to sell more than 23,000 apartment units to Starwood Capital for $5.4 billion. The sale represents over 20 percent of the Equity Residential portfolio.

The fund plans to sell another 4,700 apartment units in the near future. Most of the proceeds will be returned to investors in the form of a dividend sometime next year.

Another real estate fund managed by Zell, Equity Commonwealth, has sold 82 office properties worth $1.7 billion since February. The fund plans to raise another $1.3 billion by selling off more properties over the next few years.

Mauldin Economics

Zell is cashing out of non-core assets after the run up in real estate prices in recent years. Rather than reinvest, much of the cash is being returned to investors. The message he is sending is clear—it’s time to sell.

High prices + rising interest rates = time to sell

REITs (real estate investment trusts) have been one of the hottest investment sectors in the aftermath of the 2008 credit crisis.

REIT prices are up 286% from their March 2009 low, compared to 209% for the S&P 500 over that same period. Real estate prices have benefited greatly from the Federal Reserve’s aggressive stimulus packages and zero-interest rate monetary policy.

Real Capital Analytics data showed that commercial property values across the country reached the highest level on record in August—up 14.5% on a nominal basis and surpassing the previous inflation adjusted mark from 2007 by 1.5%.

Mauldin Economics

High prices have led to record low cap rates (cap rates measure a property’s yield by dividing the annual income by the property value). The average cap rate on all property types across the US hit 5.25% in September. This breaks the 5.65% low from 2007, according the Green Street Advisors.

The data dependent Fed has trapped itself in a corner. On the one hand, they can see that property values and stock markets have skyrocketed. On the other hand, real economic growth appears to have stalled.

The Fed has tried to signal an end to its easy money policies all year long. However, poor US economic data and fear of a global slowdown has kept them from taking action.

Still, the potential for higher interest rates has caused REIT investors to take a pause. Higher interest rates make dividend yields from REITs less attractive than the safer alternatives, such as Treasury bonds. It also makes it more costly to finance new acquisitions and real estate developments.

Warning signs

The S&P US REIT Index has underperformed the S&P 500 benchmark so far this year. If this holds, it will mark only the second year since 2009 that REITs have underperformed the S&P 500 index—the other being 2013, when the Fed began its process of backing out of its aggressive bond-buying program.

Mauldin Economics

Sam Zell is not alone. Over the last twelve months, insiders were net sellers of shares at all but one of the top ten funds on the index.

Mauldin Economics

And the institutional money has started to follow suit as well. Five of the top ten REITs on the index had net outflows from institutional investors as of the most recent quarterly filing.

Mauldin Economics

As Steven Roth, CEO of Vornado Realty Trust, said on an investor call in August, "The easy money has been made in this cycle... this is a time when the smart guys are starting to build cash." You can choose to ignore the writing on the wall or perhaps it's time for investors to follow the smart money and move their cash out of real estate.