Private equity group Hellman and Friedman has bought CSG and Iris Software from HgCapital - the firm's previous private equity owners.
The newly-combined firm will trade as Iris Software Group with turnover of more than £100m. Iris specialises in accounts software, while CSG provides software to lawyers and not-for-profit concerns.
No value was put on the deal, although Hellman and Friedman said it had "enterprise value" of £500m - this is a theoretical price including debts. H&F will be the majority shareholder, but HgCapital will keep a stake in the firm.
HgCapital funded the management buyout of Iris in 2004 and completed the acquisition of CSG in April 2007.
In other private equity news, consultancy and software firm Civica watched its shares in London jump more than 10 per cent this morning after the company confirmed an approach from an unnamed private equity group.
The public sector specialist said: "The board of directors of Civica plc announces today that it has received an unsolicited preliminary approach from a private equity fund. Discussions are at an early stage and this approach may or may not lead to an offer being made for the company. There can be no certainty that an offer will be made. A further announcement will be made in due course." ®