Google has agreed to merge with Verizon in 2019 for an annual payment of $13 billion, according to a source with knowledge of the deal.

The merger will be completed when the combined companies reach certain financial milestones, the source said, declining to be identified because the transaction is not yet public.

Google has also agreed to purchase another $2 billion of spectrum to deploy its data network in Canada, the deal said.

Verizon’s stock was down about 0.5 percent on Monday.

Google is under pressure to close a deal with a major telecom operator because of rising costs and concerns about antitrust.