China Unicom shares rose slightly yesterday after the country's second biggest wireless carrier and Spanish telecom firm Telefonica agreed to swap $1 billion stocks among each other to cement their tie-up.

Under an agreement announced over the weekend, the two telecom carriers will each buy $1 billion worth of other's shares to "strengthen their cooperation and achieve business synergy".

Telefonica, Spain's largest telecom operator, which already owns about 5.38 percent of Unicom, will boost its shares in the Chinese firm to 8 percent, according to the agreement.