U.S. company bond sales are falling, with speculative-grade issuance headed for the slowest month since December 2008, on growing signs the economy is faltering.

PepsiCo Inc., the world's biggest snack-food maker, and Glenview, Illinois-based Illinois Tool Works Inc. led $5.7 billion of sales this week, a 72 percent decline from $20.4 billion in the period ended Aug. 19, according to data compiled by Bloomberg. There were no offerings of high-yield, high-risk bonds this week, leaving August's total at $1 billion, compared with the monthly average this year of $28.5 billion.

Yields on corporate bonds have soared to the highest level since March as Europe's debt crisis worsens and economists from Goldman Sachs Group Inc. to JPMorgan Chase & Co. reduce their forecasts for U.S. growth. Central bankers are meeting this week in Jackson Hole, Wyoming, where Federal Reserve Chairman Ben S. Bernanke last year hinted at a second round of bond purchases, or quantitative easing.