Consumers burdened by their large mortgages and maxed-out credit cards laid the groundwork for the last US recession. This time, companies may play that role: Enticed by super low interest rates, they increased total debt by $2.81 trillion over the past five years, to a record $6.64 trillion. In 2015 liabilities jumped $850 billion, 50 times the increase in cash holdings by S&P Global Ratings’ reckoning. Lagging profits and mounting defaults are other danger signs. Although these financial vulnerabilities aren’t likely to lead to another downturn soon, economists say they point to potential risks for an expansion approaching its seventh birthday. “Companies have been adding to their debt, and their debt has been growing more rapidly than their profits,” says John Lonski, chief economist of Moody’s Capital Markets Research Group. “That imbalance in the past has usually led to problems” once growth begins to flag. Some are concerned that’s already happening, as evidenced by cutbacks in corporate spending and hiring. Case in point: the news that employers expanded payrolls in May at the slowest pace since 2010, in what economists at JPMorgan Chase worry is a sign of increased company caution. Also, April marked the third straight month of falling orders for business equipment. The $62.4 billion figure, which excludes defense and aircraft orders, was the lowest in five years, prompting Neil Dutta of Renaissance Macro Research to label business investment “pathetic.”