Analysts across the industry have started estimating the potential cost of the recent PSN security breach. Micheal Pachter told Shacknews that in the week that PSN has been down, Sony has lost at least $10 million in revenue and $3 million in profits.

Those direct losses are likely the least of Sony's woes though.
Indirect losses from the lack of consumer trust and confidence in the
system will likely cost much more. Legal compensation is another
potential cost. The Ponemon Institute speaking to Forbes placed the
average cost of a criminal data breach at $318 for each record lost. At
77 million registered users, that makes for a hefty sum of just under
$24.5 billion, and that doesn't take into account any costs associated
with regaining consumer trust.

Hulu has already offered a free week of service in response to the downtime to subscribers, and Kotaku says that Sony has a range of special events and compensations planned this weekend for DC Universe Online and Free Realms. Who knows what Sony will need to do for compensation to gain consumer trust in the coming months.

And of course there's the expense of making sure that this doesn't
happen again such as security investigation costs as well as rebuilding
the network. Sony has asked developers to install a new SDK with
advanced security features during the downtime to keep history from
repeating itself.

This is a seriously expensive mistake for Sony, as is seen by the 5.2% drop in Sony's stock price since the breach.
Image from Gamingbolt.com
Source: GamesIndustry.biz