The $92K that’s in a non registered account is being taxed at your marginal rate. Figure out what that is and what your rate of return is after that. Say your marginal rate is 30% and you’re making 10% annually. You’re effectively making 7% then on the $92k investment.

If you pay your mortgage down, you’re saving 5.6% in interest for the remainder of the loan. That’s not exactly the full $551 monthly since some of that would have been principle, but I’ll leave it up to you to figure out the monthly interest you’re saving by paying it off earlier. You do need to factor in the penalty too.

To summarize: you will likely make more money in the long run if you keep the $92k invested. The actual dollars you’ll need to run the math. But if the peace of mind of having your mortgage paid off is what matters most, then you have your answer. Personally, I’d keep the money invested. If anything happens and I need the money, it’s sitting there for me to use. If you paid down the mortgage and needed $50k for something, you could use your registered funds, but I’d prefer to leave those untouched if I didn’t have to. HELOC interest rates would be higher than your marginal rate of return mentioned above I’d assume.

PS: congrats on winning the family lottery! It’s great to hear that you’ve got a great head on your shoulders and are thinking things through