What happens if my Net Account Value drop below Initial Margin Requirement and above Maintenance Margin?

You will not receive any margin call and can still hold your position(s) as long as your Net Account Value still above Maintenance Margin level.

However, please monitor your account and position(s) closely. When you receive a Margin Call, you will need to transfer funds (USD) from securities account into your Futures account to restore your Net Account Value back to Initial Margin requirement.