Ticker Talk

Nasdaq Chairman Frank G. Zarb, set to retire in February, will remain in charge at the stock market for as much as a year longer, the National Assn. of Securities Dealers said Thursday. Zarb, the former White House energy czar who has presided over the Nasdaq Stock Market since 1997, will continue to work on initiatives including the spinoff of the exchange as a for-profit company, and to help ease the transition for his eventual successor.