A US activist investor has joined the bevy of companies chasing British IT firm Misys.

ValueAct – Misys’ largest shareholder with a stake of 21 percent – revealed yesterday it has teamed up with private equity firm CVC Capital Partners to work on a joint cash offer.

The news marks the third offer for the London-based company, which provides IT systems to the financial community.

In February, Misys announced an all-share merger with Swiss rival Temenos, only to see buyout firm Vista Equity Partners wade in with a cash offer.

Under the UK’s takeover code, ValueAct and CVC have until April 2 to announce a firm intention to make an offer or walk away.

Their bid could well be an attempt at ‘saber rattling’ to force the price higher, says George O’Connor, analyst at Panmure Gordon, in a note.

Formed in 2000, ValueAct has around $6 bn in assets under management.

The firm looks to invest in undervalued companies and then work with management to achieve a turnaround in the share price.

It typically holds stakes in 15-20 companies and is active in around a third of them, CEO Jeffrey Ubben told Opalesque TV last year.