Factors around the credit quality of unlisted businesses receive an overview in the quarterly Bulletin of the Reserve Bank of Australia, published yesterday. The RBA bases most of its analysis on a review of data, covering 6000 unlisted firms, from the database of credit bureau Dun & Bradstreet.Aggregate data suggests that the unincorporated sector had a more stable profit performance than the incorporated or listed sectors in recent years, the RBA concluded. In addition, arrears on bank loans to the unincorporated sector were lower.The RBA article, by Tom Bilston and Melissa Watson, pointed out that total business profits fell in late 2008 and the first half of 2009, before rebounding in the second half of the year.These fluctuations, which cover large listed business as well, were largely driven by listed companies and especially variations in the profits of listed resource companies.In the unlisted sector, the credit bureau data shows that in 2009 the median return on assets of all firms in the sample declined slightly to five per cent.Returns were widely dispersed: the top 25 per cent of firms had an ROA of around 15 per cent in each year of the sample, while the ROA of firms at the 25th percentile was only slightly positive. By industry, the highest median ROA was for construction, at an average of 12 per cent each year. Agriculture and other services industries recorded the lowest median ROAs, below three per cent, the analysis shows.The proportion of unlisted businesses in the sample making net losses increased from 19 per cent in 2005 to 24 per cent in 2009.Losses were most prevalent among smaller firms (with assets under A$1 million), where the proportion of loss-makers increased from 24 per cent in 2005 to 34 per cent in 2009. The industries with the largest shares of loss-makers were mining and agriculture. The RBA said that loans to unincorporated businesses accounted for around 16 per cent of business credit from banks and other lenders as at October 2010.The major banks provided just under 80 per cent of these, although unincorporated lending was only six per cent of their total loans. Other Australian and foreign-owned banks each accounted for around 10 per cent of bank loans to unincorporated businesses. Smaller business continues to be source a demand for net new lending from banks even as business credit declines, the RBA said.Even so, supplier credit represented around half the average liabilities of firms in the sample.