Facebook Inc. raised $16 billion in the biggest initial public offering by a technology company in history, pricing the shares at the top end of an increased range.

The social network, led by 28-year-old Mark Zuckerberg, sold 421.2 million shares at $38 each, data compiled by Bloomberg show. This week, Menlo Park, California-based Facebook expanded the IPO to meet demand, allowing backers Goldman Sachs Group Inc. and Accel Partners to reap more gains.

The offering marks the culmination of Facebook's evolution in less than a decade from a Harvard University dorm-room project into a social network with more than 900 million users. While Zuckerberg persuaded investors to buy the shares at a higher price-to-earnings multiple than almost every company in the Standard & Poor's 500 Index, he now faces stemming slowing sales growth after profit fell 12 percent last quarter.