D&B ( DNB), a business information company, said Wednesday that it has acquired Open Ratings for $8 million in cash. Waltham, Mass. -based Open Ratings provides risk management solutions to manufacturing companies. It posted revenue of $4.5 million in 2005. Dun and Bradstreet expects the deal to reduce its 2006 earnings by about 2 cents a share, most of which is in the first half, and add to its 2007 earnings. The acquisition will have no impact on its 2006 full-year guidance, the company said in press release.