The speculative-grade default rate resumed its upward march in May, reports Moody’s Investors Service.

The rating agency says that the global speculative-grade corporate default rate rose to 9.2% from 8.3% the previous month. A year ago, the rate was just 1.9%.

Moody’s now predicts that the global default rate will peak at 13.8% in the fourth quarter of this year before falling to 8% by May 2010. In the U.S, the automotive sector is seen as the most troubled, whereas the durable consumer goods segment is expected to produce the most defaults in Europe for the remainder of the year.

“Moody’s default rate forecasts from its forecasting model have been declining in recent months as high-yield bond spreads have narrowed significantly. Still, spreads remain at very elevated levels by historical standards,” said Kenneth Emery, Moody’s director of default research.

A total of 29 Moody’s-rated issuers defaulted in May, pushing the year-to-date default total to 141. Only 30 defaults were recorded in the same period
last year.

Measured on a dollar volume basis, the global speculative-grade bond default rate reached 13.3% in May, up from a revised 12.9% level in March. Last year at this time, the global dollar-weighted default rate was just 1.2%.

One positive sign is that Moody’s speculative-grade corporate distress index, which measures the percentage of rated issuers that have debt trading at distressed levels, fell from May’s revised level of 51.8% to 42.8%.