NEW YORK, April 18 (Reuters) - High-speed trading firm Virtu Financial Inc, which has been pursuing an initial public offering, has received a letter of inquiry from the New York attorney general amid a wider probe of the industry, a person familiar with the matter said on Friday.
News of the request by the office of New York Attorney General Eric Schneiderman came amid heightened attention to high-frequency trading following the publication of author Michael Lewis' book "Flash Boys: A Wall Street Revolt" last month.
Schneiderman's office had earlier sent subpoenas to more than half a dozen high-speed trading firms including Tower Research Capital LLC, Chopper Trading LLC and Jump Trading LLC, a person familiar with the matter previously told Reuters.
Federal agencies including the Justice Department, Securities and Exchange Commission and Commodity Futures Trading Commission have also said they had active probes into high-speed and automated trading.
Virtu's IPO, which was expected in April, was seeking to raise about $200 million to $250 million, valuing the firm at about $3 billion.
Reuters reported earlier this month that Virtu delayed the launch of its IPO as it awaited regulatory approval, which was expected within days rather than weeks.
A person familiar with the matter said on Thursday that Virtu has not set a date to go to market with the IPO at this time.
Shares of KCG Holdings Inc, a firm that engages in electronic market making practices similar to Virtu, are down 16.7 percent since the beginning of April.
A spokesman for Schneiderman declined comment on Friday. News of the letter of inquiry was first reported by Bloomberg News.
(Reporting by Mike Stone and Nate Raymond in New York; Additional reporting by Karen Freifeld; Editing by Marguerita Choy)