The global recession boosted corporate downgrade rates to a new high in 2009, says Fitch Ratings in a new report.

The rating agency says that the recession “affected nearly every corner of the credit markets in 2009. No sector or region was left unscathed — credit erosion was widespread.” And, as a result, 26.7% of the global corporate issuers it rates were affected by downgrades. This was up from 20.1% in 2008, and, at the same time, upgrades fell to 4.7% from 6.5% a year earlier.

Investment-grade issuers didn’t fare much better than speculative issuers, with investment-grade downgrades reaching 26.1% in 2009, up from 19.3% the previous year; while non-investment grade issuers saw a downgrade rate of 28.2%, up from 22.1% in 2008.

“The recession’s impact on corporate credit quality was especially severe in the first six months of 2009 which saw 80% of the year’s negative rating actions,” said Charlotte Needham, senior director of Fitch Credit Market Research.

Global financial institutions experienced more credit erosion in 2009 and 2008 than industrials. The share of financial entities downgraded reached 33% in 2009, topping 2008’s 22%. The share of industrial issuers downgraded in 2009 was 20%, up from 18% a year earlier.

The economic stress was also reflected in defaults, as “Debilitated financial markets and a deep contraction in economic activity, especially in the first half of the year, pushed the default rate on Fitch-rated corporate issuers up to 2.59%, double the rate of 1.29% recorded in 2008.” Although it notes that the year’s defaults were concentrated among non-investment grade issuers, as they accounted for 93% of all 2009 defaults. For investment grade issuers the default rate for the year was just 0.24%, down from 0.57% in 2008.