Just 14 months after becoming head of trading at Sanford C. Bernstein & Co., online innovator Matt Andresen is out. Though the news was kept strictly hush-hush, Institutional Investor has learned that the onetime day trader and former CEO of Island ECN resigned on February 1. Why? Sources familiar with the matter say that the 33-year-old iconoclast with the shaved head had been at loggerheads with Lisa Shalett, Bernstein's CEO since November 2002.

"There was no love lost between them," says one person close to the situation.

Shalett's predecessor, Sallie Krawcheck, won high praise in the securities industry when she hired Andresen to help the firm deal with rapid changes in market rules and technologies. Andresen had built Island, an upstart trading outfit run by a handful of 20-something techies, into a leading electronic communications network; it handled as much as 20 percent of the Nasdaq's volume before it was acquired by Instinet in September 2002. But within a few weeks of landing Andresen, Krawcheck decamped for a much bigger job as head of Citigroup's Smith Barney brokerage unit. When Shalett, a Bernstein veteran who, like Krawcheck, had been an equity analyst and director of research at the firm, took over as CEO, things changed for Andresen. Though some had viewed him as a potential successor to Krawcheck, Andresen did not get along personally with Shalett the way he had with Krawcheck.

His employment contract expired on January 31, and neither he nor Bernstein had any interest in renewing it. Shalett declines to comment on Andresen's departure except to confirm that it happened. Andresen says only that he is looking at future employment opportunities, adding, "I'm considering a number of things."