As trading starts to wind down for Tuesday, shares of cruise...

As trading starts to wind down for Tuesday, shares of cruise line stocks are winding back up. As of 3:35 p.m. ET, $Norwegian Cruise (NCLH.US)$ (2.83%) stock is sporting a 3.2% gain, followed by $Royal Caribbean (RCL.US)$ ( 3.99%), which is rising 3.7%. Leading the whole pack higher, meanwhile, is industry bellwether $Carnival (CCL.US)$ （4.48%), up 4.6%.

And indeed, it turns out that Carnival is the source of today's good news -- because Carnival has announced it's sailing in the wake of Norwegian Cruise Line and changing its COVID-19 policies to attract more customers.