A version of this article first appeared in the CNBC Property Play newsletter with Diana Olick. Property Play covers new and evolving opportunities for the real estate investor, from individuals to venture capitalists, private equity funds, family offices, institutional investors and large public companies. Sign up to receive future editions, straight to your inbox.

Fundamentals in the multifamily apartment market are weakening as a historic surge of new supply continues to make its way through the pipeline and rental demand falls back. At the same time, investor demand for these properties is rising.

As an example, Camden Property Trust, a top-10 multifamily real estate investment trust, quietly began marketing its entire California apartment portfolio — 11 properties valued at roughly $1.5 billion — a few weeks ago and has already had significant interest.

“We have a huge demand for it right now,” Ric Campo, CEO of Camden, told CNBC. “Not two or three, but hundreds.”

Campo said the company wants to focus entirely on the Sun Belt, which is where 90% of its properties are now.