Baby boomer business owners preparing for retirement are driving a surge in the sale of small businesses, as they find more and more buyers confident enough in the improving economy to expand their own businesses through acquisitions.

In the first three months of this year, the number of sales that closed jumped 56 percent from the same time in 2012, according to BizBuySell.com, an online marketplace for small businesses. Retirement was the No. 1 contributor to business sales in the fourth quarter of last year and the first quarter of 2013. Buyers appear to be ready to step up and are looking for companies that will be good fit with their existing operations. Health-care related businesses like medical billing firms, pharmacies and even medical and dental practices are particularly in demand, says Keystone’s Richards. He’s seeing less interest in restaurants and retailers, industries where profit margins are thinner and where many companies are still struggling.

Sellers are benefiting from this trend because buyers are willing to pay more money if a deal will quickly get them into the markets they want to serve, says Mike Carter, CEO of BizEquity, a company that helps businesses calculate their sales price.