FUN ▲ +2.8% - Six Flags Entertainment Corporation $FUN - Six Flags Introduces Flex Pay by Upgrade, Allowing Guests a New Way to Plan and Pay for Fun Six Flags Entertainment Corporation (FUN) rose 2.8% today following the company's announcement of a new payment option called Flex Pay by Upgrade, which enables guests to spread out payments for park visits and purchases. The new financing tool could broaden the company's addressable customer base by lowering the upfront cost barrier to attendance. 07-SEP-2026 07:30 AM ET