(Dow Jones) It's generally accepted that the mutual fund investor has been pulling his money out of the U.S. stock market since, and because of, the 2008 financial crash. The truth is, it's more complicated than that.

Investors have indeed yanked hundreds of billions of dollars out of so-called retail classes of domestic stock funds, such as those they traditionally buy directly from fund companies or through a financial advisor working on commission.

But at the same time, they've actually poured money into so-called institutional shares. As the label suggests, these are used by pensions, endowments and other institutions--but they also are frequently used by 401(k) plans and fee-based financial advisors.

"There are a lot of factors at work," says Morningstar analyst Syl Flood, adding that different funds' tendency to allow investors to use different share classes for different purposes, makes reading even clear cut-seeming trends devilishly tricky.

One possible interpretation is that financial advisors are not holding the line when worried investors declare they've had enough of stock losses. In that scenario, advisors appear to have allowed clients to jump out of the market, a move many investing experts believe should be avoided.

A contrasting take, however, is that the financial crisis has accelerated a decade-long shift in which advisors are abandoning commission-based business models in favor of fee-based ones, and that more and more they are also seeking the cheapest fee-oriented share classes. The trend may even suggest investors are putting greater faith in financial advisors than ever before, since fee-based accounts can mean advisors have more input into clients' investment decisions.

The dynamics aren't mutually exclusive and there is outside evidence to support both. Morgan Stanley Smith Barney, for instance, says it is in the process of moving investor dollars into institutional share classes from retail classes in its fee-based advisory accounts, although specific numbers are proprietary. Meanwhile, data from research firm Cerulli Associates show growing popularity over the past several years for types of brokerage accounts that let investors boost cash holdings above typical levels.

Overall, investors have yanked about $90 billion from domestic stock mutual funds since the start of 2009 when the market was near its nadir, according to Morningstar Inc.

But, in fact, the total shows two very different stories. Investors have pulled more than $162 billion from funds' retail share classes, including about $129 billion from Class A, B, and C shares, the classic so-called 'load' shares that investors traditionally buy when they work with a commission-based financial advisor. They've also pulled about $55 billion from retail no-load share classes, the kind they buy when they purchase shares in some fee-based brokerage accounts or directly from fund companies.

At the same time, inflows into institutional share classes, which are frequently held in 401(k) plans or by investors in fee-based brokerage accounts overseen by financial advisors, amounted to $72 billion.

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