Originally Posted by
ziqch
How long do you have to keep the account open to get these miles from ameritrade,
While you have failed to identify
which program's miles you are asking about, as a general rule the terms and conditions for each offer do an excellent job of answering your question.
For example:
http://www.tdameritrade.com/offer/pa.../starwood.html
Account must remain open with minimum funding for 9 months, or TD AMERITRADE may charge the account for the cost of the Starpoints.