(Adds details from financial results, background on hack)
Nov 9 (Reuters) - Equifax Inc on Thursday reported a lower third-quarter profit as costs from the credit reporting bureau's recently disclosed data breach that exposed deeply sensitive information on 145.5 million people began to mount.
Net income attributable to Equifax fell to $96.3 million, or 79 cents per diluted share, from $132.8 million, or $1.09 per diluted share, a year earlier.
Adjusted for one-time costs, such as hacking- and merger-related expenses, Equifax said it earned $1.53 per share, beating an average of analysts' estimates by 4 cents, according to Thomson Reuters I/B/E/S.
The Atlanta-based company recorded $27.3 million of pre-tax expenses related to the cyber breach, which occurred between mid-May and late July and involved the theft of data such as birth dates, Social Security and credit card numbers.
The expenses included costs to investigate and remediate the cybersecurity incident and legal and other professional services related thereto, all of which were expensed as incurred, the company said. (Reporting by John McCrank in New York; Editing by James Dalgleish)