Fidelity Investments has confirmed a data breach that affected the personal information of more than 77,000 of its customers, Cointelegraph reported. Fidelity filed documents with the Maine Attorney General on Oct. 9, stating that 77,099 customers were affected, a small fraction of its 51.5 million customers.

The attackers accessed customer names and other personally identifiable information through two newly established customer accounts between August 17 and 19. The unauthorized access was discovered and terminated on August 19.

Fidelity said outside security experts helped resolve the issue and stressed that no third party had accessed any Fidelity accounts. Fidelity is offering two years of free credit monitoring and identity restoration services to those affected who register with TransUnion Interactive.

This is Fidelity’s fourth data breach in the past 12 months, with the previous three occurring on March 4, March 18, and July 19. Fidelity launched spot Bitcoin and Ether ETFs in the United States this year.