MHA MacIntyre Hudson, which sits at number 19 in the Accountancy Top 60 League Table, has announced it is to merge with Reading based practice, HMT Assurance.
The move will see three partners and 19 staff move under the MHA banner, joining MHA's existing operation which constitutes 496 staff and 42 partners at 10 offices around the UK.
The firms are understood to have been in negotiation for about 18 months, before finalising the details of the merger.
'A lot of the smaller firms are looking for opportunities to provide better and wider offerings to their clients and we felt they were of size where they were looking at life from that perspective,' said MHA chairman Rakesh Shaunak.
He said that from that point, the partners approved the process within 10 days, after MHA's management board approved the approach.
Shaunak said there would be no redundancies, since this was in essence a new office for MHA.
According to Accountancy's latest table, MHA's fee income went up to £35.2m in 2012, from 2011's £32.4m.
The new firm could, according to Shaunak, nudge the £40m mark going forward.
HMT is set to continue providing services for audit, tax and business advice from Reading.
The firm's partners, all of whom are ex-Big Four, are understood to be experienced in areas pertaining to transition and restructuring and corporate transactions.
'The three new partners bring their background of the Big Four and good working relationship with their former firms, particularly where the Big Four are conflicted out of doing additional work for a client. We're hopeful this will lead to additional work for us to pick up on,' Shaunak said.
'We see it as having lots of opportunity for us and believe we have found the right team to lead the way based in the Reading office,' said Shaunak.
Jason Mitchell, partner at HMT Assurance LLP, said the merger would benefit clients, broadening the range of services and sector expertise for HMT's clients.
He added that previous Big Four experience, at both partner and staff level at HMT, was one of the key trading points during the merger.
'It's something to sell to clients - Big Four experience delivered through a smaller practice. We still have many friends within the Big Four and under the new environment, the Big Four are conflicted out of some work for independence reasons.
We're lucky enough to pick up a lot of work through that. For similar reasons, in the area of tax, we've been lucky enough to be given the opportunity by some of the bigger firms to help large plcs and listed companies,' said Mitchell.
He said that being part of MHA would also increase HMT's reach both nationally and internationally through MHA and Morison International as well as offering access to professionals specialising in, for example, VAT, employment tax, outsourcing and corporate recovery. 'We believe the ongoing high quality delivery from our experienced team supported by the wider resources of a larger organisation will give our clients the right blend of professional service and strong personal relationship,' said Mitchell.