A quarter of Europe's unrated leveraged buyouts will default by 2015, according to a report by Moody's.
The rating agency warned this figure might double if the continent's high-yield bond market collapses for extended periods owing to economic uncertainty.
The study revealed that 254 European deals had a total of €133bn of debt due by the end of 2015, with more than half owed by 36 borrowers.
It is unclear which companies are unrated by Moody's, but experts believe it includes mega cap deals such as Alliance Boots, the largest ever leveraged buyout in Europe. The UK is the most exposed, with some €54bn of debt that is due to mature over the next three years.
Prior to the financial crisis, the European credit market was dominated by banks and collateralised loan obligations, specialist vehicles set up to buy the debt used in LBOs. Banks have little appetite to continue their exposure to the market, and CLOs are due to mature soon. Unlike the US, European companies rarely tapped bond markets.