Coventry accountants Pilley & Florsham is advising Microsoft on its new software accounting package for small businesses.
The Warwick Road firm is one of a select number throughout the UK to be asked to trial the new software and advise the US giant on modifications.
Laurence Moore, a partner, said it had been approached during the early stages of the software's development, which is Microsoft's first foray into the low-end of the bookkeeping market.
The invitation is seen as a coup by Pilleys, whose reputation for IT innovation was first recognised when the firm was made a member of the prestigious Independent Association of Accountants Information Technology Consultants (IAAITC).
"We are the only firm in the region to be assisting Microsoft with this project, a recognition of our heavy involvement in helping SMEs use IT to produce their management information and accounts," said Mr Moore.
The head of Pilleys management accounts department Colette White put the Microsoft product through its paces before going to Reading to advise the Microsoft team on her suggested changes.
"It is based on their US software but because of the difference in language, financial regulations and VAT matters, there had to plenty of amendments for the UK version," said Mrs White, who has 20 years at Pilleys.
"The development programme is on-going and we will be working with Microsoft over the next three months to streamline the software," she said.
Meanwhile, Microsoft's first dedicated security product has gone on sale in the US.
The product, called One-Care, rolls anti-virus, antispyware and firewall programs into one package. It also includes back-up software that helps people recover important data in the event of problems. Those signed up to the service will also get alerts about emerging threats and advice about what they need to do to counter them.
The software, which has been in development for three years, is aimed at consumers and small businesses which currently have only the most basic protection against netborne threats.
Microsoft plans to roll out OneCare internationally over the next 12 months.