Corporate defaults may almost double in Europe as companies struggle to refinance debt and banks hoard cash borrowed from the European Central Bank or use it to buy government bonds.

Europe's default rate may soar to 8.4 percent or more, from 4.8 percent at the end of 2011 as the recession bites and company financing dries up, according to Standard & Poor's. Petroplus Holdings AG became the latest victim of the tough stance banks are adopting when the region's biggest independent oil refiner said this week it will file for insolvency after losing access to $2.1 billion of credit lines.

"It's very challenging for anyone to raise money from lenders right now," said Andrew Cleland-Bogle, a Frankfurt- based director at corporate finance specialist DC Advisory Partners. "Combine that with increased bank capital requirements and you can see that although banks are getting money they're very selective when it comes to lending it. 2012 is going to be a very, very tough year."