SMALL COMPANIES TRADING over the counter have a tough time attracting dollars from such conservative investors as pension-fund managers, who prefer to take their roller-coaster rides in amusement parks. But new financial instruments that are due next winter may reduce the risk and help companies raise money.

Pending regulatory approval, the National Association of Securities Dealers and the Chicago Board of Trade plan to begin trading put-and-call options and futures contracts on an index of about 100 of the largest nonfinancial NASDAQ stocks. By trading these contracts, investors can bet on whether the over-the-counter market -- represented by the stocks on the index -- will go up or down. Several indexes already exist for stocks listed on the New York and American exchanges.

The effect of index options is a matter of controversy, but some experts say these options could open new sources of capital for small companies. Investors can use them as side bets to hedge investments in individual stocks. Such hedges "will make all the underlying stocks of the index more attractive for purchase," says Alvery Bartlett, president of Stock Index Futures Inc., a St. Louis-based brokerage. Institutional investors who think that lightly capitalized companies are too risky may reconsider. Established small companies may find it somewhat easier to issue new stock, and stock prices in general might creep slightly higher.

Index contracts guard against changes only in general market conditions. So stocks that move independently of the market are less likely to benefit from index contracts.