Warren Buffett has been moving his personal investments from safe Treasury securities into U.S. stocks, according to an opinion piece he wrote in Friday's New York Times.

If prices continue to look attractive, the legendary investor says he expects his personal account to be 100 percent invested in U.S. equities, the legendary investor wrote in the article.

The piece, titled "Buy American. I am," reiterated one of the legendary investor's favorite maxims: "Be fearful when others are greedy, and be greedy when others are fearful."

"Most certainly, fear is now widespread, gripping even seasoned investors," said the so-called Oracle of Omaha.

"To be sure, investors are right to be wary of highly leveraged entities or businesses in weak competitive positions," Buffett said. "But fears regarding the long-term prosperity of the nation's many sound companies make no sense. These businesses will indeed suffer earnings hiccups, as they always have. But most major companies will be setting new profit records 5, 10 and 20 years from now."

Not everyone was immediately convinced that Buffett's strategy is for them.

"His position is probably the opposite of what someone close to his age should be doing: keep more of their money in Treasuries," said Charles Geisst, a finance professor at Manhattan College and the author of "Wall Street: A History."

"I understand the sentiment, but this situation is unlike anything we've seen since 1932," he added. "In downturns such as 1987 and early this decade, we never had a real clear view of what caused markets to go down. In this case, we have much too clear a view. This is the first time we've seen systemic problems affect the markets since the Great Depression."

Since stocks began to tumble in September, Buffett and his investment company, Berkshire Hathaway Inc., have made large bets on U.S. companies, exacting rich dividend payments in the process.