CMS has entered into a co-operation agreement with Portuguese firm Rui Pena Arnaut & Associados (RPA).

The agreement, which was signed in October last year, will see the nine-member network of European firms work with RPA on cross-border deals, as well as providing client referrals.

The work shared with RPA will focus on corporate, employment, energy, intellectual property and tax. CMS chairman Cornelius Brandi said the association would be important in developing the network's wider strategy across the Iberian region.

"With its strong presence in Portugal, RPA provides CMS and our clients with an important element in our European offering," he said. "Already the co-operation is bearing fruit for the clients of both parties and we look forward to building our relationship further."

RPA is a full-service firm based in Lisbon with associated offices in Brazil and Angola.

The news comes after it emerged last week that CMS member firm CMS Cameron McKenna has called on its partners to contribute additional cash, with the firm upping the amount of capital paid in by equity partners by £1,000 per equity point.