Shares in spin-off companies and their parents have outperformed the US equity market in the past 15 years, according to research by Lehman Brothers.

Several US conglomerates have announced plans to divest parts of their businesses into standalone companies. Tyco International last month approved plans to split into three units. Lazard advocated a four-way split of Time Warner this month when it advised corporate raider Carl Icahn on his campaign to break up the US media group.