Lehman Brothers and Fidelity Investments, the largest US mutual fund company, have launched an equity trading tie-up aimed at boosting liquidity and cutting information leaks, building on the relationship they forged through an unbundling agreement in October 2005.

Lehman and Fidelity's brokerage unit have agreed to link their alternative trading systems in a move the two companies hope will broaden the trading possibilities for their clients by granting access to a wider pool of liquidity, they said in a joint statement today.