The smallest businesses have the highest percentage of past-due accounts receivable, according to an analysis of Dun & Bradstreet's U.S. database on more than 9 million firms.

According to the study, an average of 22 percent of all receivables are reported as past due.However, the Dun & Bradstreet (D&B) study revealed that among firms employing more than 50 workers, the percentage of past-due receivables was nearly constant at 20 percent. In contrast, the nation's smallest firms, those employing fewer than 10 workers, reported 27 percent of their receivables as overdue.

"Small businesses tend to take on riskier accounts," said Joseph W. Duncan, corporate economist and chief statistician for D&B, the world's largest marketer of business information services. "At the same time, they generally lack the resources to collect on stubborn past-due receivables."

From an industry perspective, the analysis showed that wholesalers get paid faster than other businesses. Past-due receivables accounted for only 17 percent of total receivables for wholesalers, compared with 22 percent for all firms.

Past-due receivables accounted for 21 percent of all retailers' receivables. However, within the retail sector, the ability to collect receivables on time varied. For example, only 11 percent of receivables were overdue among auto dealers, compared with 31 percent among apparel merchants.

"Car dealerships are well-known for their stringent default provisions," Duncan said. "On the other hand, credit requirements for clothing stores tend to be less strict and, hence, subject to more risk."

The construction sector reported past-due receivables of 34 percent, the highest among all nine industry sectors.

"The pattern among construction firms reflects the high levels of subcontracting in the business, combined with a significant rise in vacancy rates during the past year," Duncan said.

The study revealed that 30 percent of all government receivables are overdue, while 28 percent of all receivables in the mining industry, which includes oil and gas extraction businesses, are late.

"Cash flow problems have plagued the mining sector since the oil market bottomed out three years ago," Duncan said.