Equifax Inc (EFX.N) said on Friday it expects US$275 million in costs in 2018 related to the credit reporting company's massive data breach last year, offset by US$75 million in insurance proceeds.

The costs mainly reflect technology and data security upgrades, legal fees, and free identity theft protection and credit monitoring offered to the more than 147 million consumers affected by the cyber security incident, the company said in a conference call.

Equifax on Thursday reported fourth-quarter profits that topped Wall Street forecasts after earlier in the day disclosing that an additional 2.4 million people were affected by the cyber attack.

So far, the Atlanta-based company has recorded breach-related expenses of US$114 million, net of insurance recoveries.

Equifax said in September that criminals had breached its systems and stole personally identifiable information of U.S., UK, and Canadian consumers, including names, Social Security numbers, birth dates, addresses and, in some instances, driver’s license and credit card numbers.

"It is possible that further analysis will identify additional consumers affected or additional types of data accessed," Equifax said in a regulatory filing on Thursday.

As a result of the 2017 cyber security incident, Equifax said it was the subject of numerous class action lawsuits, as well as investigations by U.S. federal, state, local and foreign governmental officials and agencies.

Equifax shares were up 2.1 per cent at US$113.87 in early trading.