Trades are not placed on the days that markets are closed. You can still place orders in your Stockpile account and they will show as "Pending" until they can be processed the next day the market is open.
Money movement, like deposits from or withdrawals to your bank account could be delayed an extra day due to the holidays.
Stockpile is closed on the following stock market holidays:
New Year’s Day - Tuesday, January 1
Martin Luther King, Jr. Day - Monday, January 21
Washington's Birthday - Monday, February 18
Good Friday - Friday, April 19
Memorial Day - Monday, May 27
Independence Day - Thursday, July 4
Labor Day - Monday, September 2
Thanksgiving Day - Thursday, November 28
Christmas - Wednesday, December 25