Sony has placed an estimate on the total damage brought about by the cyber attack against Sony Pictures Entertainment in December.

The sum, which covers "investigation and remediation costs," has reached $15 million.

Sony had to provide forecast results as opposed to actual results for its movie unit's performance in the third quarter of the fiscal year. The cyber attack massively disrupted the company's network and infrastructure, leaving Sony to request an extension in the filing of its earnings report.

The attack, which the FBI believed was instigated by North Korea, compromised the company's confidential information. The group of hackers known as Guardians of Peace claimed responsibility for the attack that occurred in late November.

The main reason for the series of attacks against Sony was the comedy film The Interview, whose release the company initially postponed after receiving threats that movie houses would be blown up. Apart from postponing the movie, the company also delayed the release of its financial report in order to have more time to fully explore the impact caused by the hack.

"The current quarter is expected to include approximately $15 million in investigation and remediation costs relating to the above-mentioned cyber attack," said Sony when it released its financial forecast. "Sony believes that the impact of the cyber attack on its consolidated results for the fiscal year ending 31 March 2015 will not be material."

Sony originally intended to release its earnings for the third quarter of the fiscal year on Feb. 16. This will cover earnings for the months of October to December. However, the company had to make the most of the information available and release its forecast at a company-held press conference on Feb. 4.

Sony's third-quarter results had forecast a loss of $1.4 billion for the fiscal year, which is an improvement from an earlier forecast of a $1.9 billion loss. In the past fiscal year, the company reported a loss of $341 million.

Sony's forecast shows that apart from the video games, the company's movie and music businesses have all benefited from the weakened value of the Japanese yen against the U.S. dollar. The company has decided to sell its Vaio computer business and to split off its TV division, which will run as a wholly owned subsidiary.

Sony also noted that a decline in its mobile business will result in a massive number of job losses. However, the company is confident it will be able to counter the result with the sales of the PlayStation 4, which are stronger than expected. Other reasons include a slight improvement in the financial services business, robust sales of devices and higher network services revenue.