New York's top banking regulator has issued subpoenas to roughly two dozen companies associated with bitcoin as part of a wide-ranging inquiry into the business practices of the fledgling virtual-currency industry, according to people familiar with the matter.

The subpoenas, from the New York Department of Financial Services, seek information on a range of topics, including antimoney-laundering programs, consumer-protection measures and investment strategies, according to the people.

The department, led by Benjamin Lawsky, also plans on Monday to issue a memo expressing concern that virtual-currency companies aren't complying with the state's money-transmission laws. As a result, the state is considering setting new guidelines that are specifically aimed at virtual currencies.

"We believe that—for a number of reasons—putting in place appropriate regulatory safeguards for virtual currencies will be beneficial to the long-term strength of the virtual-currency industry," wrote Mr. Lawsky in a draft of the memo reviewed by The Wall Street Journal.

Companies that received subpoenas include some of the best-known names in the nascent industry, including Coinbase Inc., BitInstant and Coinsetter.