US consumers generally expect there to be no pre-payment penalty. That isn’t a universal feature of all loans. As to particular features of particular loans ask the really expensive lawyers or investment bankers who negotiated them, but plausibly “I owe you $45M; here’s a new equity investor; we’re done after the wire clears right.” might lead to “We agree you owe us $60M.”
I remember when I was just out of college, I was warned that there was such a thing as a mortgage that did not allow for extra payments, and that you should check for that when applying.
If you couldn't, or even if you did the payment incorrectly, anything extra would just be treated as if you sent your payment in for the subsequent month a little early. I've heard of the latter happening to friends, but I've never seen or heard of the former.
Many loans you have to be careful that you don't pay them like that. If you don't specify that you're paying down principal with the extra, it just goes toward next month's payment. So next month you might only owe $50 instead of $500.
US consumers generally expect there to be no pre-payment penalty. That isn’t a universal feature of all loans. As to particular features of particular loans ask the really expensive lawyers or investment bankers who negotiated them, but plausibly “I owe you $45M; here’s a new equity investor; we’re done after the wire clears right.” might lead to “We agree you owe us $60M.”