Business Post which is based at Heartlands, Birmingham, announced its acquisition of BXT yesterday.
Paul Carvell, chief executive of Business Post which has a turnover of pounds 72.9 million, said BXT would not be absorbed but allowed to remain as a free standing company within the group while allowing it to take advantage of more than 60 Business Post depots in the UK.
BXT has 150 employees, whose jobs remain unaffected by the takeover, and at the close of its books on July 31 at the end of its last full-year it had a profit of pounds 300,000 on a turnover of pounds 4.3 million.
Nicholas Terry, chairman of BXT, will remain with the company for a further 12 months in a consultancy capacity.
BXT operates in three sectors - utilities, which includes delivering water samples and specialised work around that business, and the IT and medical sectors, which includes work for several hospital trusts including Good Hope at Sutton Coldfield.
Mr Carvell said: 'This is not a business area that we are in, our courier business is more noncontractual and for us it is a good opportunity to offer BXT's services to our customers and vice versa.
'We investigated national companies and got down to a short list of interesting businesses and BXT was one of them.