Significant Stock Market Movements: Cigna and Macy's Rise, Southern Copper and RingCentral Fall

Key events include Cigna's $10 billion stock buyback, Occidental Petroleum's acquisition of CrownRock, and Macy’s receiving a buyout offer.

Cigna Group announces a $10 billion stock buyback and discontinues pursuit of Humana, causing its stock to rise.
Occidental Petroleum Corp. acquires oil and gas company CrownRock in a deal valued at about $12 billion.
Shake Shack Inc. announces the retirement of CEO Randy Garutti in 2024.
DoorDash Inc. will join the Nasdaq 100 Index as of December 18.
Macy’s Inc. reportedly receives a buyout offer from Arkhouse Management and Brigade Capital Management.