In commerce, middle-market companies or mid-market companies are generally those companies with revenues between US$ $10 million and $1 billion per year according to the most authoritative references including the Economist and the National Center for the Middle Market at the Ohio State University Fisher College of Business, while other definitions exist. At the uppermost end of the middle market, those companies with $1 billion in revenues are generally the smallest eligible for a credit rating by one of the "major" credit-rating agencies.