Facebook Inc. reported a plunge in fourth-quarter profit on higher spending, even while it made long-awaited progress luring advertisers eager to reach mobile- device users.
Net income fell 79 percent to $64 million last quarter as operating expenses jumped 82 percent, Facebook said Wednesday. That outpaced a 40 percent revenue gain to $1.59 billion and raised concerns that margins will come under pressure. The stock fell as much as 8 percent as investors weighed near-term lower profit against the prospect of future growth.
