As per the BBC about 143 million US customers of credit report giant Equifax may have had information compromised in a cyber security breach.
Some UK and Canadian customers were also affected.
The firm's core consumer and commercial credit databases were not accessed.
Equifax said hackers accessed the information between mid-May and the end of July, when the company discovered the breach.
Malicious hackers won access to its systems by exploiting a "website application vulnerability", it said but provided no further details.
The hackers accessed credit card numbers for about 209,000 consumers, among other information.
Equifax said it had set up a website - www.equifaxsecurity2017.com - through which consumers can check if their data has been caught up in the breach. Many people trying to visit the site reported via social media that they had problems reaching it and that security software flagged it as potentially dangerous.
Unsurprisingly shares in Equifax took a hit.
#Equifax shares plunge after #databreach potentially impacting 143 million #Americans - https://t.co/WR95l5QsIr #equifaxhack #privacy— Marc R Gagné MAPP 🌐 (@OttLegalRebels) September 8, 2017