Over at the New York Times Dealbook,  the man responsible for a $6 billion hedge funds says just that in an article by Alexandra Stevenson: 

Mr. Spitznagel, the founder of Universa Investments, which has around $6 billion in assets under management, says the stock market is going to fall by at least 40 percent in one great market “purge.” Until then, he is paying for the option to short the market at just that point, losing money each time he does.

….

Mr. Spitznagel’s approach is unusual approach for a money manager: To invest with him, you’ve got to believe in a philosophy that is grounded in the Austrian school of economics (which originated in the early 20th century in Vienna). The Austrians don’t like government to meddle with any part of the economy and when it does, they argue, market distortions abound, creating opportunities for investors who can see them.

When those distortions are present, Austrian investors will position themselves to wait out any artificial effect on the market, ready to take advantage when prices readjust.

Apparently his primary reason for this coming purge, which he says is needed, is that the Fed will have to readjust its monetary policies at some point. When they do, he says, the purge will come.  

I am no expert in monetary policy, but I have wondered how long we can sustain an economy with interest rates so low.  My recollection was that one of the Fed's key powers was to be able to raise and lower interest rates to spur growth or temper inflation.  With interest rates this low, it seems that power is greatly restricted on both counts.  I tend not to be one who thinks the sky is falling, but there is at least some reason to believe it may be getting a bit cloudy.