Bitcoins, which exist only online, have no central managing authority, and their owners are anonymous.
According to the person familiar with the probe, the firms receiving the subpoenas included online payment systems Dwolla, Coinbase, BitInstant and Coinsetter. The regulator also targeted investment firms including Google Ventures, Andreessen Horowitz and Winklevoss Capital Management, the firm controlled by Cameron and Tyler Winklevoss, who famously battled Mark Zuckerberg over the ownership of Facebook.
In the memo, the state regulator explained that firms engaged in "money transmission" must comply with a variety of regulations, including a requirement that they post collateral, submit to safety and soundness examinations and comply with anti-money laundering laws.
"It is in the common interest of both the public and the virtual currency industry to bring virtual currencies out of the darkness and into the light of day through enhanced transparency. It is vital to put in place appropriate safeguards for consumers and law-abiding citizens," Lawsky wrote.