Over the past year, Jeffrey Vinik has been doing what he's always wanted to do: time the market without having to answer to a bureaucracy.

The former Fidelity Magellan fund skipper, now head of Vinik Asset Management, had $6.8 billion in equity investments at the end of the second quarter, according to SEC filings. That sum is up from only $422 million in equities at the end of 2008. But at the end of the second quarter in 2008, his hedge fund had $11.8 billion invested in stocks.

Vinik returned most of the money in his hedge fund to his 160 investors in 2000. Now he manages money for wealthy friends, family members and a few long-time investors he has allowed to stay in his fund.

A person familiar with Vinik said he's not timing the market per se - that he is still the fundamental, bottom-up research oriented manager he has always been. He just happens to have gotten very bearish in the second half of 2008, like a lot of other hedge fund managers.

But Vinik did display flourishes suggesting market timing even on his watch at Fidelity Magellan, which he ran from 1992 to 1996. He shifted more than 35% of the stock fund's portfolio into bonds and cash in the mid-1990s, prompting criticism when the market drop he feared didn't materialize immediately. Eventually, it did.

Don Phillips, a managing director at Morningstar, said the stock picking is indicative of how Vinik learned to invest, in the mold of famed Magellan manager Peter Lynch. "Vinik," Phillips said, "was the golden child." He felt less comfortable when Fidelity, in the 1990s, reined in money managers' independence.

Vinik left Fidelity and set up his own shop, which had immediate success betting on technology stocks and adept timing in getting out of them before the Internet bubble burst.

The flexibility of running money for a select few - rather than for investors in one of the most scrutinized mutual funds in the world - allows Vinik to add and subtract from his equity positions from quarter to quarter without having to defend his decisions. Lately, he has taken advantage of that flexibility.

Going from $11.8 billion to $422 million is "definitely extreme," said Sam Norvell, senior vice president of Hennessee Group, an adviser to hedge fund investors. While not talking about Vinik personally, Norvell pointed out that many hedge-fund managers turned bearish at that time because of fears about financial institutions and something even more unpredictable, government intervention.

But just as quickly as it turned into a bear, Vinik became a bull during the first half of this year. The firm took more than 200 new positions during the first half, and its top holdings include an exchange-traded fund that invests in gold, Green Mountain Coffee Roasters Co. (GMCR) and an old favorite for Vinik, Google Inc. (GOOG). Vinik sold out of a long-standing Google position at the end of 2008, only to buy back in this year.

Vinik doesn't take positions of more than 5% in most of its holdings, according to filings. Many of those holdings are large-cap stocks that can be hard for a single investor to move when buying or selling.

Vinik's moves into and out of the market seem timely, but it couldn't be determined what the fund's return has been. The firm is so secretive that it doesn't even use corporate email. Jeffrey Vinik did briefly fall into the spotlight in 2007 as a limited partner of the Boston Red Sox, when his son Danny caught a foul ball over the glove of an Anaheim Angels outfielder's glove, prolonging an at-bat that led to the Red Sox tying, and eventually winning, a playoff game.

The SEC filings don't say how Vinik reduced its exposure to stocks. The firm could have moved money into credit instruments, lowered leverage in its funds, paid investors their money, or a combination of those things. Jeffrey Vinik wouldn't comment for this article.

-By Joseph Checkler, Dow Jones Newswires; 212-416-2152; joseph.checkler@dowjones.com