San Francisco ? Online retailer eBay Inc., which is trying to reverse years of slowing growth in its auctions business amid rising competition and a spreading financial crisis, said Monday that it would cut 10 percent of its global work force even as it spends $1.3 billion to buy three Web businesses.

Even after the largest reduction in its 13-year history, which eBay said would save $150 million in annual operating costs, the San Jose, Calif., company saw its shares tumble by as much as 12 percent to their lowest level in more than five years. They recovered to close at $17.89, down 5.5 percent.

Investors are concerned that eBay’s bread and butter, online auctions, is showing increasing vulnerability to slowing consumer spending, the slumping U.S. house market and high fuel prices.

EBay’s latest slide was part of a broad sell-off of technology stocks. Analysts say the high-tech industry is firmly in the grip of the economic turmoil it had hoped to sidestep. Companies such as Microsoft Corp., Google Inc. and Yahoo Inc. are re-evaluating their staffing levels, and giants such as Hewlett-Packard Co. already have cut jobs to be more efficient.