Last week was a rough ride for the stock market, capping off what so far has been a lackluster month. Falling 318 points on Friday alone, the Dow Jones Industrial Average (^DJI) sold off more than 3% last week. In the last month the Dow and S&P 500 (^GSPC) are both down low-single-digits on a percentage basis. And Monday, the sell-off continued, led by emerging markets, as European stocks fell following sharp drops in Asia.

The global angst expressed in equity markets has been attributed to concerns about China's economic slowdown, fears over emerging markets and expectations that the Federal Reserve will further scale back its bond buying.

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TrimTabs Investment Research focuses on the supply and demand of shares of stock, and the money available for investment. Charles Biderman, portfolio manager of the TrimTabs Float Shrink ETF, tells us "fund flows are surprisingly small this January." He reports very little inflow into U.S. equities by mutual funds or ETFs, which he says "is somewhat surprising given there were huge inflows in the fourth quarter of last year."

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In Biderman's view, a belief that the U.S. economy was going to grow sustainably allowing the Fed to taper caused everyone to jump in the market. He believes the sentiment has shifted with people now thinking maybe the economy isn't growing all that well, with problems in emerging markets and the Fed not printing as much money.

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January is the first month the Fed has scaled back on bond buying, purchasing $75 billion in bonds versus $85 bilion in months prior. The Fed is expected to announce it will dial those purchases down further, to $65 billion, after its meeting this week.

Biderman had previously thought last year's rise in stock prices would continue through January, because he tells us, he really thought we would see big inflows this month -- "there always have been following up a very strong market. It reallly surprised me there were no inflows to take stock prices higher."

Just how accurate are these fund flows in forecasting what happens with the market? Between 2009 and 2012 the stock market rise occurred despite retail outflows. Biderman says the "Federal Reserve swamps individual activity." He says there were outflows, however, the Fed was pumping huge amounts of money into financial assets -- "the Fed was inflating the cash available for financial assets."

So what happens as the Fed continues scaling back on quantitative easing purchases, and perhaps stops completely? Check out the video to find out.