In the context of stock in your brokerage account, a standing order is a direction that either dictates which shares to sell first or states that you will specify the shares to use for each sale. This matters for the cost basis used in tax reporting, which is also part of the new Form 1099-B. The standing order can be FIFO (first in, first out), LIFO (last in, first out), or HIFO (highest basis in, first out). The broker or another agent can also be given full or limited power to decide. Changes are allowed at any time up to the settlement date. If you specify which shares are sold, this must be done before the settlement date for the trade.

If you have company stock in your account from various types of equity compensation, such as shares from ISO exercises and restricted stock unit vesting, when you sell the shares be sure that you sell the ones you want. Selling other shares unintentionally may trigger unwanted tax consequences (e.g. a disqualifying disposition of ISO stock). This situation may require a change in the standing order.