Why is there a maintenance requirement for securities in a margin account with equity 100%?

External question — Personal Finance Stack Exchange Author: Joe Original post: https://money.stackexchange.com/questions/148501 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. In TD Ameritrade, margin accounts show a maintenance requirement for the account even if no loan was used to purchase any of the securities. Why is this? How could a margin call ever happen if no margin was used? Also, even with cash in the account that would cover a stock purchase, a given order registers a margin balance before the trade closes. Does the broker use margin as a way to quickly fulfill an order and then settle with cash at a later time? Does this trigger the need to calculate a maintenance requirement for the entire account?

External answer — Personal Finance Stack Exchange Author: Bob Baerker Original post: https://money.stackexchange.com/a/148516 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. TD is telling you what the margin requirement is for your account. It's not reflecting existing use of margin. So if you had $10k of fully paid securities, it would indicate that the margin requirement is $5k. As for the a account, there is no margin involved with security transactions. Settlement is T+2 which means that the respective brokers have two days to settle the trade with cash going one way and the security going the other.