Optima Tax Relief over the weekend confirmed it notified 3,114 people of a May 2025 data breach that compromised their Social Security numbers and financial account numbers.
Ransomware gang Chaos took credit for the breach, saying it stole 69 GB during the attack.
Optima has not verified Chaos’ claim. We do not know if Optima paid a ransom, how much Chaos demanded, or how attackers breached Optima’s network. Comparitech contacted Optima for comment and will update this article if it replies.
“We identified unusual activity in our network on May 1, 2025,” says Optima’s notice to victims. “The investigation determined that an unauthorized person accessed the network between May 1, 2025, and May 6, 2025, and downloaded copies of certain files.”
Optima is offering eligible victims one year of free identity monitoring through Kroll.
Who is Chaos?
Chaos is a ransomware gang that first surfaced in 2021 but didn’t start claiming victims on its data leak site until March 2025. The group attacks both individuals and organizations through drive-by-downloads and phishing. It employs a double-extortion scheme in which victims are extorted both for stolen data and to restore infected systems.
Chaos has made 10 attack claims so far, two of which were acknowledged by the targeted organizations. Optima Tax Relief is one of them.
The other is IES Communications, which notified 6,241 people of a March 2025 data breach. Optima says it stole 1 TB of data from IES.
Ransomware attacks on US finance
Comparitech researchers have logged 22 confirmed ransomware attacks on American financial firms in 2025 to date, compromising more than 167,000 records.
In another recent claim, ransomware gang Inc over the weekend took credit for a July 2025 attack on accounting firm Potts, Steele, and White.
Last week, Kranz Consulting notified 75 people in Massachusetts of a June 2025 data breach. The firm says it paid the ransom to avoid the exposure of confidential data.
Ransomware groups have made another 131 unconfirmed attack claims against US financial companies in 2025 so far.
About Optima Tax Relief
Optima Tax Relief is a tax resolution firm. Customers who owe taxes pay Optima to reduce their tax burden and deal with the IRS. It employs more than 400 people.
