The move comes in the wake of similar deals for Adapt in September (£30 million) and Access in March (£50 million). The Clearswift acquisition will cost the private equity firm more than £30 million, Infosecurity understands.
Clearswift's customer base for its security technology, which manages inbound data threats, data loss prevention and web access policies, includes BAE Systems, Hitachi and T-Mobile.
Under the arrangement announced today, Clearswift's CEO Richard Turner will be joined on the board by Lyceum partners Jeremy Hand and David Harland. Martin Leuw - the former CEO of Iris Software - also joins the board, as chairman, to guide the business through its next phase of growth.
Hand, the co-founder of Lyceum Capital, said that the move will see his firm backing an exciting company, which deploys world-class technical expertise and software solutions across an exceptionally impressive and loyal customer base.
"With an already strong management team bolstered by the arrival of Martin and our strategic, operational and financial input, we're expecting Clearswift to continue with its strong organic growth supplemented with targeted acquisitions", he said.
Richard Turner, Clearswift's CEO, meanwhile, said that with threats and risks increasingly becoming specific to individual customers, they need a tailored and more flexible approach.
"The one size fits all anti-spam and anti-virus technologies many companies rely on is out-dated. With its heritage in both content inspection and flexible compliance policies backed up by excellent service, Clearswift is well positioned to meet customer needs in a world where social media and web technologies are rapidly transforming the way we all do business", he said.
"We are delighted to have the backing of Lyceum Capital to support the next phase of our ambitious growth plans."