trim tabs' leon merochnik believes much of the selling is inevitable as baby boomers prepare for retirement. >> since march of '09, the dow jones has gone up more than 75%. that huge appreciation has a lot of investors saying, "let me realize my gains at the moment." and because they're getting closer to retirement, "let's back off that equity allocation, let's go more into bonds." >> reporter: but not all the money is going into bonds or cash. surprisingly, some of the proceeds are also going into small-cap mutual funds. not only are they one of the riskiest sectors of the market, they are lagging large caps in performance this year. >> investors still are gravitating toward what worked in the past. so, when they are looking at their financial statements and fund reports, they are seeing track records based on 2009 and 2010, and they're not really focused on what's happening in the marketplace now and what the go-forward aspect is now. >> reporter: but there's an even bigger shocker. at the same time money is coming out of u.s. stock mutual funds, it has been going into large-cap exchange