Lazard's planned initial public offering will have to be squeezed into a three-month window after its chief executive, Bruce Wasserstein, told the investment bank's partners that the deal was unlikely to be launched before April 2005.

A person close to Lazard said the bank had missed a mid-November deadline to make its regulatory filing with the US Securities and Exchange Commission. Under US regulations, this means Lazard will have to wait until it has full third-quarter results before seeking regulatory approval for its float.