Verizon says it's locking its phones down to combat theft

Verizon said that it would begin locking the phones it sells to consumers, which will prevent them from using a SIM card from another carrier. Initially, the phones will be unlocked as soon as a customer signs up and activates the service. But later in the spring, the company will begin the practice of keeping the phone locked for a period of time after the purchase -- in line with the rest of the industry. 

Verizon said it is doing this to deter criminals from stealing phones, often on route to retail stores or from the stores themselves. Unlocked phones make attractive targets because they can be resold on the black market or used overseas with different carriers. The move marks a broad reversal of its policy to offer all of its phones unlocked -- part of a deal with the Federal Communications Commission requiring it to unlock phones as part of its acquisition of the "C block" of 700 megahertz spectrum, which powers its 4G LTE network. While Verizon said it will unlock the phones eventually, there's concern that the company is reneging on its commitment.