The Capita Group has bought three of the Wynchgate Group's four businesses for £18.6m, including its insurance broking business.
Capita paid £10.3m in cash, 1,315,101 new ordinary shares and £4m in loan notes.
Another £8m in deferred payment is dependent on future performance up to March 2005.
The key purchase among the three businesses, Best is the UK's biggest provider of staff absence and associated cost management services to the state education sector.
Its client base includes 42 local education authorities and more than 2,000 schools.
Capita Group executive chairman Rod Aldridge said that Best's innovative solutions would be introduced to Capita's existing client base of 156 local education authorities and 23,000 schools.
He said Capita would also help Best enter new markets in the public and private sectors.
Best's managing director Gary Salter will remain with the company as a director.
The two other businesses acquired were Wynchgate Insurance Brokers and Wynchgate Holdings.
Wynchgate Holdings managing director Peter Walters will also stay on as a director.
Wynchate Group retained Wynchgate Financial Services.
