If you have any doubt, I would call Continental. They're not as quick about informing investors unlike Computershare is for GME. I was worried, too, when I first registered my shares with them, as I never heard if my shares were secured, either. Also as a heads up, any voting that needs to be done with those shares (like the merger) will have materials sent via snail mail, too. I still have shares with my broker, and I always get proxy material first via email. Continental will send out the material, but it might be a couple weeks after the voting window has opened.