In the latest symptom of Europe's financial turmoil, the region's riskier companies are bypassing banks and investors at home and turning to the U.S. for loans.

European companies borrowed some €14.4 billion (about $18 billion at current rates) in the U.S. leveraged-loan market this year through Friday, more than double the €6.7 billion for all of 2011, according to data from S&P Capital IQ LCD. That is the highest amount since at least 2007, the height of the last boom in leveraged lending, when full-year loan volume was...