Technology stocks) dropped sharply on Monday,

SAN FRANCISCO (Reuters) - Technology stocks including Facebook (FB.O), Microsoft (MSFT.O) and Alphabet (GOOGL.O) dropped sharply on Monday, increasing worries that the top-performing sector is falling out of favor as investors look elsewhere for cheaper opportunities.

Facebook fell 4.6 percent, on track for its worst day in nearly a year and eliminating over $20 billion of its market value, while Microsoft, Apple (AAPL.O) and Alphabet each lost more than 1 percent.

Those stocks have helped push the S&P 500 information technology index .SPLRCT 23 percent higher in 2017, making it the top performer among the S&P 500’s main sectors.

Underscoring growing concerns about a shift in investor focus, a quarter of the 68 stocks in that technology index have seen recent drops of 10 percent or more, which many on Wall Street define as a correction.

“There’s definitely some panic out there,” said Wedbush trader Joel Kulina. “Everyone is talking about rotation, it’s becoming one of those buzzwords.”