WASHINGTON -- Federal Reserve Chairman Alan Greenspan, who boldly goes where few others go in the economic-policy universe, plays it safe when it comes to his own investments.

Alan Greenspan

Solid ground is his preference on personal financial matters. Greenspan keeps all of his holdings in money market accounts and Treasury securities, which are considered the world's safest investment, a financial disclosure form shows.

Also, papers released Thursday show that the Fed chief avoids any appearance of conflict that might be raised by stock holdings in individual companies.

The value of his assets last year totaled between $3.3 million and $6.4 million, roughly the same as in 2003, according to new disclosure forms. The figures need only be given in broad ranges.

Greenspan, who is 79 and expected to retire from the central bank next year, has urged Congress to deal with the looming financial crisis of the Depression-era Social Security retirement system. The system faces massive strains as a wave of baby boomers begin retiring in 2008. The Fed chief also has called on upcoming retirees to make sure they have their own financial houses in order.

"Retirees are going to need something like 80 percent of their immediately pre- retirement income to maintain a reasonable standard of living," Greenspan said at a congressional hearing last week. " And that means a very substantial part of retirement resources is going to come from other than Social Security out of necessity."

The disclosure form also showed that Greenspan's income from his no-frills investments, which also include savings and checking accounts, totaled between $33,800 and $80,700. That's down from the range of $43,226 to $102,300 that Greenspan reported in investment income in 2003.

Greenspan also was paid a $174,500 salary for being Fed chairman last year. This year his salary rose to $180,100. The Fed chief's salary isn't included on the disclosure form.

As chairman of the central bank, Greenspan has helped steer the U.S. economy -- the world's largest -- through both periods of smooth and choppy economic waters.

To help rescue the economy from the 2001 recession and the jolts of the Sept, 11, terror attacks, Greenspan and his Fed colleagues in a series of moves sliced short-term interest rates to rock-bottom levels. With the economic recovery firmly planted, the Fed over the last year has been pushing rates up to more normal levels.

Greenspan's wife, NBC News correspondent Andrea Mitchell, had separate investment holdings valued at between just more than $1 million and $2.5 million in 2004. Those assets generated income of around $27,300 to $81,200 last year.

Mitchell's holdings include stock in Abbott Laboratories, Anheuser Busch Companies, H.J. Heinz, Wal-Mart, Kimberly Clark and Pfizer.

She also was paid thousands of dollars in honoraria last year. Those payments included $40,000 from the Jewish Federation, $19,000 from Fairfield University, and $10,000 from the Carlyle Group.