The respective shareholders of office landlord Government Properties Income Trust and diversified real estate investment trust Select Income REIT approved the companies' proposed merger at their separate Dec. 20 special meetings.

At Government Properties' meeting, 90.1% of the shares that voted were in favor of the issuance of the company's common shares in the merger. At Select Income's meeting, 68.6% of the outstanding shares and 88.3% of the shares voted in favor of the tie-up.

The companies expect the merger to become effective Dec. 31, with the merged entity to be called Office Properties Income Trust and its shares to trade on the Nasdaq under the OPI ticker.

Under a stock-for-stock merger deal announced in September, the companies agreed to combine to create new a REIT with undepreciated gross assets worth $6.1 billion.