(A digest of investment opinion from the world's leading financial advisers)

Martin Zweig, whose Zweig Forecast (P.O. Box 5345, New York, N.Y. 10150) has been the top-performing newsletter for the past 10 years with a 481 percent appreciation, believes the stock market would be in trouble even without the Mideast crisis. According to Zweig, the average NYSE stock has broken its long-term bull market trend line, which goes back to 1974. Zweig is currently more than 80 percent in cash.- Prudential-Bache Global Genesis Fund has been in business only two years. But they have been two very successful years, with 32 percent and 30 percent appreciations. Portfolio manager Cassandra Hardman focuses on small overseas companies with low price-earnings ratios, strong earnings momentum and solid long-term promise. Recent favorites: Dyckerhoff (Germany, cement); Horten (Germany, retailer); Schneider (Germany, consumer electronics); Sita (Italy, waste management); Tachekawa Blind (Japan, window blinds); and Cabin (Japan, clothing retailer).

- Unlike property-casualty insurers, most life and multiline insurance companies aren't plagued by real estate and construction loan problems. Nor do they have a significant percentage of their assets in junk bonds. Still, the stock market has been treating them as if they did. United & Babson Investment Report (101 Prescott St., Wellesley Hills, Mass. 02181) believes this misconception will eventually change, and recommends four life and multiline stocks with low prices and rosy business prospects: American International Group, Capital Holding, Jefferson-Pilot and Torchmark.

- Investors often confuse small-capitalization stocks with secondary stocks. They shouldn't, says Binkley Shorts of the Over-the-Counter Securities Fund. "Secondary stocks usually have more dramatic operating leverage, leaner profit margins and greater sensitivity to pricing changes, whereas small-cap stocks can be industry leaders and their prospects are now much brighter." Shorts recently recommended eight promising small-caps with single-digit P.E.s: Cimco, Devcon, Fab-ric-land, Helen of Troy, Rauch, SKI Ltd., Varlen and Wolohan Lumber.

- "We dislike annuities that guarantee their rates for only one year but have a penalty period on redemptions lasting much longer," says Personal Finance (1101 King St., Suite 400, Alexandria, Va. 22314). "If interest rates fall and you take your money out, their redemption penalty will really sting. So we're pleased to have tracked down four annuities which guarantee their rates for five years or more: American Investors Guarantor 5, National Home Life MVP, Federal Home Life SPDA, Fidelity and Guaranty Life SPDA."

- Real estate mutual funds, limited partnerships and investment trusts are passive, liquid investments that many real estate experts despise. "They're for investors who are too frightened to go out on their own," says Real Estate Investor's Monthly (342 Bryan Drive, Danville, Calif. 94526). "It's not in the laws of economics to come strolling into real estate, where the returns can be 25 percent annually or higher, and not do anything. If you want to sit on your hands, buy a government bond and get 9 percent."

- Stocks are much more volatile than bonds. But if you can ride out the dips, they pay off much better, too. According to Weber, Lipshire & Co. in New York City, $1 invested in 1926 in common stocks had grown to $535 by 1989, whereas $1 invested in intermediate-term Treasury bonds had become $22 and $1 in Treasury bills had become only $10.

Investor's Notebook reflects the opinions of professionals. It does not endorse specific investments, and no endorsement is implied or should be inferred. For more information, contact the individual firms cited. 1990 Universal Press Syndicate 4900 Main St., Kansas City, Mo. 64112