The Florida Attorney General’s office on Thursday said it is investigating Green Dot Corp. and four other prepaid debit card providers for possible deceptive and unfair practices.

Attorney General Pam Bondi said the state is looking into hidden fees associated with the cards and “misrepresentations promising to improve consumers’ credit scores.”

Headquartered in Monrovia, Green Dot is considered one of the pioneers of prepaid debit cards, which have become increasingly popular with low-income customers and others without bank accounts. The reloadable cards are available at tens of thousands of locations, including many Wal-Mart and 7-Eleven stores.

Green Dot Chief Executive Steve Streit issued a statement saying the company does not charge hidden fees and will cooperate with the investigation.

“Green Dot’s fee policies and disclosures are well-vetted and well-regarded and we take our stewardship as a consumer-focused company seriously,” he said.

Besides Green Dot, the attorney general also issued subpoenas to Netspend Corp. in Austin, Texas; First Data Corp. in Atlanta; Account Now Inc. in San Ramon and Unirush Financial Services LLC in Cincinnati.

Green Dot’s shares closed down $1.86, or nearly 5 percent, to $38.56 on the New York Stock Exchange