Some of the most speculative "penny" stocks sold by fast-pitch brokers over the telephone would come with a money-back guarantee, if congressional reformers have their way.

Under new legislation intended to attack penny-stock fraud, investors who buy shares in a shell company -- one that has no stated business -- will be entitled to get their money back if they don't like the kind of business the company eventually goes into.

The money-back guarantee was a key element of penny-stock legislation approved yesterday by the House subcommittee on telecommunications and finance, headed by Rep. Edward J. Markey (D-Mass.).

The bill now goes to the House Energy and Commerce Committee, where approval is expected.

Sales of stock in shell companies are called "blank-check" offerings because investors give the companies a free hand to do anything they want with the shareholders' money.

Government investigations have found that blank-check offerings frequently are used by stock manipulators to defraud investors. Blank-check offerings also represented 31 percent of all initial public offerings in 1989.

The terms of the penny-stock bill, which had bipartisan support, were worked out with the Securities and Exchange Commission, which oversees stock offerings; the National Association of Securities Dealers, which runs the over-the-counter market and regulates securities firms; and the North American Securities Administrators Association, which represents state regulators.

Joseph I. Goldstein, head of the SEC's penny-stock task force, said, "I think the objectives of the bill are excellent. It will go a long way toward addressing the problems of penny-stock fraud."

Investors lose an estimated $2 billion a year to penny-stock frauds.

Initially, Markey sought to ban all blank-check offerings, but the SEC argued that a ban would fly in the face of the SEC's basic charter -- to protect investors by requiring companies that sell securities to disclose everything about themselves.

Under that philosophy, a company can win SEC approval for its stock offering even if it tells investors: "We have no business and no employees. We're selling stock to raise money. But we don't know what we're going to use it for."

Instead of banning blank-check offerings, the revised bill will require the SEC to demand more disclosure from blank-check companies and to prevent them from using the money raised in the offerings until the disclosures are made. That would be in addition to giving shareholders the right to ask for their money back.

From 1985 through 1989, the SEC recorded 2,031 blank-check offerings out of 8,932 total initial public offerings, or almost 23 percent of the total.

Blank-check offerings constituted 31 percent of the total offerings in 1988 and 1989.

In penny-stock fraud cases, the SEC has found, promoters secretly sell shares from blank-check offerings to friends to keep control of the stock. Then they turn around and create several waves of buying and selling among gullible investors, each time raising the price of the shares.

When the promoters have made their money, they quit the market, let the price collapse and the investors are wiped out.

"I think the use of new blank-check offerings will decline markedly as a result of this legislation," Goldstein said.

But he added that penny-stock manipulators had shown great skill in devising new ways to defraud investors.

The proposed legislation does not affect so-called "blind pool" offerings in which a company states a general business purpose, such as raising money for oil well drilling once the company finds a site.