United Rentals said this week that the U.S. antitrust waiting period related to its acquisition of RSC Holdings has expired without objections. The expiration of the waiting period satisfies one of the requirements for the deal to close.

However, United Rentals and RSC received supplementary information requests from the Canadian Competition Bureau in order to complete its review of the proposed transaction. The request has the effect of extending the waiting period under the Canadian Competition Act up to 30 days after compliance with the request. Despite the delay, both United Rentals and RSC are optimistic that the transaction will close during the first half of 2012.

United Rentals, based in Greenwich, Conn., is No. 1 on the RER 100. Scottsdale, Ariz.-based RSC Rentals is No. 2.