Spot gold surged to break above the psychological milestone of $4,600 an ounce on Monday for the first time, as safe-haven demand and expectations of rate cuts kept bullion a favored asset. Gold, silver stocks and ETFs jumped in overnight trading.

Hecla Mining rose 6%; US Gold and Coeur Mining rose 5%; ProShares Ultra Gold, Gold Fields, Agnico Eagle Mines, and Barrick Mining rose 3%.

ProShares Ultra Silver rose 5%; Hycroft Mining rose 4%; Pan American Silver rose 3%; iShares Silver Trust, First Majestic Silver, Endeavour Silver, and Fortuna Silver Mines rose 2%.

Walmart will replace British drugmaker AstraZeneca in the Nasdaq-100 Index on January 20, the exchange operator said on Friday. Walmart rose 2.2% in overnight trading, while AstraZeneca fell 1.7%.

Low-cost airline Allegiant will acquire Sun Country Airlines in a deal valued at about $1.5 billion, including debt, the companies said on Sunday. Sun Country Airlines shares jumed about 12% in overnight trading, while Allegiant dropped more than 3%.