Investing in corporate spin-offs is a time-proven strategy for beating the market, and 2007 will offer up a lot of opportunities to buy what many big corporations no longer want. Among the higher-profile deals will be Tyco International's plans to set up its electronics and healthcare businesses as freestanding units and Morgan Stanley's long-expected divestiture of the Discover credit-card unit. Just how good have spin-off returns been? A recent Lehman Brothers study found that from 1990 to 2005, spin-offs beat the Standard & Poor's 500-stock index by 18% on average in their first two years of independence. Most recently, an index of spun-off companies complied by clear Asset Management in New York beat the S&P 500 by almost 11 percentage points a year over the past five years.