Avid Life Media, the owner of infidelity dating website Ashley Madison, is being investigated by the US Federal Trade Commission (FTC), company executives said.
Last year, hackers stole the personal information of millions of the website's customers, which helps link up married people who wish to cheat.
The hack led to an internal shake-up.
Chief executive Rob Segal and president James Millership took the helm in April, Avid Life said on Monday.
The two told Reuters they did not know the exact focus of the FTC's investigation.
A spokesperson for the commission declined to comment on the investigation.
The FTC's consumer protection unit can investigate cases where consumers were told their information was secure, but was then handled recklessly or inappropriately.
In 2015, hackers published the data stolen from Ashley Madison, exposing the personal information, including names, of the website's users.
'Life is short, have an affair'
Ashley Madison- which uses the slogan "Life is short, have an affair" - has faced a mounting list of investigations and lawsuits since the website was hacked.
In a statement on Monday, Mr Segal said: "The company is truly sorry for how people's lives and relationships may have been affected by the criminal theft of personal information."
The company plans to spend millions of dollars improving its cyber security and Mr Millership said its aim was "to rebuild Ashley Madison as the world's most open-minded dating community."
In 2014, another of Avid's dating sites, JDI Dating, paid $616,165 (£473,268) to settle an FTC investigation into that site's use of computer programs that created fake profiles, known as fembots. The use of fembots was judged to be misleading to customers.
Ashley Madison was also exposed for using fembots in 2015. The website used these programs to strike up conversatiosn with paying male customers. The website has a five to one male to female ratio.
Avid said it shut down these fake profiles in the US, Canada and Australia in 2014 and the rest of the world by 2015.