General Electric said on Tuesday that a company laptop containing the names and Social Security numbers of 50,000 current and former employees was stolen in early September. The laptop, issued to a GE official who was authorized to have the data, was stolen from a locked hotel room, the company said. The Connecticut-based company began mailing letters earlier this week to the people whose names and Social Security numbers were on the laptop, to notify them of the breach and to offer a year’s free access to a credit-monitoring service.