Companies across the US are expected to feel the effect of credit market turmoil on their bottom lines in the second-quarter earnings season, with experts expecting greater writedowns and losses on illiquid auction rate securities.

In an example that could be repeated elsewhere, Aventine Renewable Energy, an Illinois-based operator of ethanol plants, recently slashed $30m off the value of $127.2m of student loan auction rate securities (ARS) that it owned, selling them for $97m.