Yields on bonds issued by many of Mexico’s leading companies have risen sharply in the past few weeks, signalling growing doubts about the ability of some to repay debts amid current market turmoil.

In the case of Cemex, the Monterrey-based buildings materials supplier and the world’s third-largest cement manufacturer, the yield on $62m of its dollar bonds maturing in October 2009 reached 41.2 per cent on Friday, a rise of almost 37 percentage points in the past month.