An older database of Zacks Market Research was accessed by an unauthorized party, compromising the personal data associated with 820,000 users' Zacks.com accounts.

The company, which offers financial markets research, disclosed the breach as required to the Maine attorney general, and reported that the cyberattack occurred sometime between November 2021 and last August. Specifically, the records of Zacks Elite product customers who signed up between 1999 and 2005 were accessed, the company explained in a letter notifying those impacted users.

"Also, while Zacks is constantly monitoring and updating our system to safeguard customer information, including in consultation with our outside cybersecurity expert, as a result of this incident, we are conducting an investigation and continuing our ongoing efforts to evaluate and implement additional measures to further enhance our protocols for the protection of your personal information," the company said.