The Office of Fair Trading (OFT) is considering an investigation into Xchanging, the provider of claims and business processing to the London Market.
The move follows accusations from London Market software provider Eurobase. which says XChanging is using its monopoly position to tender aggressively for contracts to supply IT and software.
Eurobase claims Xchanging has won at least one contract without going through the open market tender process.
A spokesman said: "In the past any start-up insurer in the London Market would be given an unofficial list of software suppliers. These suppliers would then have to go through a competitive tender process.
"XChanging is abusing its market position."
An OFT spokesman confirmed it had received complaints and was considering the issue.
