Litigation involving securities and mortgage fraud in the US is expected to climb this year as Wall Street draws more scrutiny from investors and regulators for its role in the sub-prime crisis.

According to an April report from accountants PricewaterhouseCoopers, plaintiffs last year filed 37 sub-prime related federal securities litigation cases, mostly in the second half of the year. Three of the cases, or 8%, were directed at investment banks, though it does not name them, while 51% were aimed at loan originators and 5% at the ratings agencies.