Global commercial property giant CB Richard Ellis has said it will sever links with Irish estate agent Hamilton Osborne King (HOK) in favour of an alliance with domestic rival Gunne.

The decision comes as CB prepares to formalise its takeover of Insignia, a company which has for several years controlled a shareholding in Gunne's commercial property wing.

CB has until now maintained a close link with HOK, a relationship which has helped the firm become an Irish leader in the UK commercial property investment market.

The decision to break the successful tie, which will see HOK drop CB's name from its brand, came as a surprise to industry observers, since HOK's international business is significantly more substantial than that of Gunne.

HOK's managing director, Mr Aidan O'Hogan, said yesterday that the firm was "naturally disappointed" that its relationship with CB was ending.

He indicated, however, that HOK would be considering new international alliances over coming weeks.

"For our own part, there are several other leading property consultancy groups watching the process from the wings," Mr O'Hogan said. He described the company's new position as both a challenge and an opportunity, adding that HOK had "exciting plans" to build on the €1.5 billion in overseas property it had already acquired for Irish investors.

When Gunne's new relationship with CB is complete, the firm will trade as CB Richard Ellis Gunne.

The company's managing director, Mr Pat Gunne, yesterday expressed satisfaction at CB's decision.

He said Gunne would now "aggressively" focus on developing its international business, adding that he wished HOK "every success".