Information provided by Theflyonthewall.com

JPMorgan (JPM) shares fell 7.5% after the bank announced that it suffered a $2 billion trading loss attributed to a trader referred to as the "London Whale."

CEO Jamie Dimon said the losses revealed "egregious" failures in its risk management and admitted the losses could deepen this quarter and beyond. The news gives ammunition to backers of a strict version of the so-called Volcker Rule, which would limit trading by banks for their own accounts.

Among the notable gainers Friday were Arena Pharmaceuticals (ARNA), up 63%, after an FDA panel voted that data demonstrate that the potential benefits of its weight loss drug, lorcaserin, outweigh the potential risks, and McDermott (MDR), up 14%, following an upgrade to "buy" at BB&T after the company's earnings beat expectations in spite of revenues that came in below Wall Street's view.

Also higher were shares of Advocat (AVCA), up 65%, after Covington Investments proposed to acquire the company for $8.50 per share.

Noteworthy losers included Alere (ALR), down 14%, following its disclosure of a subpoena from the Department of Health and Human Services and of the potential of broader recalls of certain Triage products after an FDA inspection, and Sony (SNE), down almost 8%, a day after the company reported steep losses in its just completed fiscal year but also said it expects to return to profit in the current year.