More companies were at risk of having their credit ratings cut at the end of December than at the close of any other year since 2009, according to Standard & Poor’s.

The number of potential downgrades was at 655, compared with 824 reported by the finish of 2009, the rating company said in a report on Tuesday. The year-end total for 2015 was "exceptionally" higher than a yearly average of 613, it said. S&P removed 85 issuers from the list in December and added 56, of which 27 are in the U.S.

The sharp decline in commodity prices over the past year, coupled with concern over a slowdown in China, have sparked defaults by oil producers from Colombia to the U.S. and Norway. Brent crude closed below $30 for the first time since 2003 last week, while benchmark stock indexes from Dow Jones Industrial Average to Nikkei 225 have lost at least 8 percent since the start of this year.