" Why would the broker need a cert" Exactly, but that's why many have been asking to rematerialise their electronically held shares into physical stock because that's the only way of knowing for sure if the trade has actually settled or not. In all honesty a broker can quite easily say that a trade has settled when in fact it might not have, especially some rookie who thinks that just because the settlement date has passed it automatically settles. It doesn't work that way. Don't forget also that without the physical stock you don't have the full shareholder rights even though you have paid for them. The more people ask now the more this will come back and haunt the MM if they don't fullfil their contract with the broker.