(FORTUNE Magazine) – CENTENNIAL FARMS MANAGEMENT CO. Founder Don Little manages portfolios of a different kind, though the assets of his Boston-based company are as unpredictable as stocks: 38 racehorses worth a total of about $15 million. The five-year-old privately held firm sells limited partnerships that each own half a dozen or so horses. Investors, who have to put up at least $40,000, share in the winnings and split the proceeds when the horses stop racing and are sold as studs or broodmares. The better the racing record, the higher the sale price. Over the past three years, about a third of the horses have won major races. Each partnership lasts for three years -- the length of a thoroughbred's racing life. Of 11 partnerships, two have been liquidated so far. The value of one grew by 200% while that of the other declined by 30%.

SAHLEN & ASSOCIATES INC. Bad news is good for this Deerfield Beach, Florida, company that provides security guard and detective services. Founded in 1981, Sahlen is thriving on fears of terrorism and white-collar crime. It has just won a large portion of a $60 million government contract to guard construction sites at 21 U.S. embassies around the world. Bear Stearns associate director David Jordon thinks the company is recession-proof. Says he: ''If the economy gets weak, theft goes up and security becomes more important.'' Sahlen expects to report profits of more than $2.5 million on revenues of $50 million for the fiscal year ended June 30. Analysts expect revenues to top $200 million in the next fiscal year because of Sahlen's pending acquisition of Globe Security Inc., a $125-million-a-year security guard service. The stock trades over the counter at $2.25, about 11 times 1988 earnings. Jordon believes the stock price is low because it is ''under-followed, under-known, and under-owned.''

VERMONT AMERICAN CORP. Spring has become a time of blossoming sales for Vermont American since the company added gardening tools to its basic line of saw blades and drill bits. Sprinklers, hoses, and hedge trimmers are the company's fastest-selling items. Vermont American, which despite its name is headquartered in Louisville, Kentucky, last year earned $18 million on $292 million in sales. Says analyst David Leibowitz of American Securities in New York: ''This company's been around since 1948, and it's a survivor.'' Vermont American trades on the American Exchange. Its recent price of $22 a share was about 11 times estimated 1988 earnings.

CRUISE AMERICA INC. Thanks to this Miami company, foreign tourists are seeing the U.S. the way many Americans do -- in a motor home. Cruise America has one of the country's largest rental fleets of recreational vehicles. With gas prices down and foreign currencies strong, demand is soaring. Founder Robert Smalley, former chief executive of Hertz, expects a 100% increase this year in rentals to foreigners. The company's average rental price is $100 a day, including mileage, for a vehicle with five beds and lots of amenities. Richard Lilly, a security analyst at JW Charles Securities, a brokerage firm in Boca Raton, Florida, expects earnings to rise 61% this year.