NEW YORK, Oct 23 (Reuters) - New York Attorney General

Letitia James is investigating whether Capital One's

proposed takeover of Discover Financial Services ( DFS )

violates the state's antitrust law.

In court filings on Wednesday, James asked a state judge to

issue a subpoena to Capital One in connection with her probe.

She said a merger could have a significant impact in New

York, with effects "particularly felt by the often vulnerable

New Yorkers with subprime credit scores."

(Reporting by Jonathan Stempel in New York)