When selling shares, etc through a stock broker, do unsettled funds always settle?

External question — Personal Finance Stack Exchange Author: Kevin Wheeler Original post: https://money.stackexchange.com/questions/134206 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. What could go wrong? Do you always end up getting the funds eventually? How long can you be delayed from getting the funds? Is there any counterparty risk of the other party not paying you the funds you are expecting after selling some stock? Edit / follow up: Let's say I sell stock in a transaction called TX1. When buying stocks with unsettled funds in a transaction called TX2, how concerned should I be about the possibility that the funds won't settle from TX1 and I will receive my shares back from TX1. Does this differ in a margin account versus a cash account? I'm aware of good faith violations, but here I'm specifically asking about the risk of TX1 not settling. What happens to TX2 in the case that TX1 doesn't settle? (Either in a margin account or a cash account).