Federal authorities, intensifying an insider-trading investigation, are demanding trading and other information from some of the nation’s most powerful investment firms.

Hedge-fund giants SAC Capital Advisors and Citadel Asset Management, big mutual-fund company Janus Capital Group Inc. and Wellington Management Co., one of the nation’s biggest institutional-investment firms, have received subpoenas from the Manhattan U.S. Attorney’s office seeking trading, communications and other data as part of a broad criminal investigation, according to people familiar with the matter. Get the full story »