46 U.S.C. § 53506 — Investment and fiduciary requirements

(a) In General. Fund money must sit in the depository named in the agreement and follow trustee and other fiduciary rules the Secretary sets. Except as (b) allows, fund money may only go into interest-bearing securities the Secretary approves. (b) Stock Investments. With the Secretary's approval, an agreed share — up to 60 percent — of the fund's assets may go into stock of U.S. corporations that (A) is fully listed on a national securities exchange registered with the SEC, and (B) a careful investor seeking steady income and safety of principal would buy. Preferred stock counts as meeting these rules, even if it's not listed because it's nonvoting, as long as the same corporation's common stock qualifies and the preferred stock would otherwise qualify too. (c) Maintaining Agreed Percentage. If the stock in the fund is ever worth more than the agreed percentage of the fund's assets, any new investment or withdrawal must be handled so as to bring the stock's value back down toward that agreed percentage.