Momentum unwind sinks US stocks
The S&P 500 fell 0.6%, the Nasdaq 100 gave back 0.8%, and the Russell 2000 retreated 0.7% to open the week.
China was a source of stock-market support, with the iShares MSCI China ETF up 7.8% after Beijing pledged more monetary and fiscal stimulus next year.
US stocks that have exhibited strong positive momentum did terribly on Monday, continuing a trend that sees the group behave opposite to Chinese stocks. The iShares MSCI USA Momentum Factor ETF fell 2.1%, lagging the S&P 500 by the most since July.
Nvidia dipped 2.6% after Chinese authorities opened a probe into the company.
Palantir had a topsy-turvy day, rallying more than 8% in the premarket before giving it all back and then some.
MicroStrategy slumped 7.5% after announcing that it had added an additional $2.1 billion in bitcoin to its digital hoard.
Communication services and utilities were the two worst-performing S&P 500 sector ETFs, while healthcare did the best.