New York's top banking regulator sent subpoenas to 22 digital-currency companies, including BitInstant LLC and Dwolla Corp., to determine whether new regulations should be adopted to govern the emerging industry, according to a person familiar with the matter.

Bitcoin is a virtual currency created four years ago that can be used to buy and sell a broad array of items, from electronics to illegal narcotics, according to the agency.

"If virtual currencies remain a virtual Wild West for narco-traffickers and other criminals, that would not only threaten our country's national security, but also the very existence of the virtual currency industry as a legitimate business enterprise," said Benjamin Lawsky, superintendent of the state's Department of Financial Services, in a statement. DFS is "considering whether it should issue new regulatory guidelines specific to virtual currencies."