How do you size a position before a data release that could move the market?

Position size decides how much a single release can cost you. The same move can be a small loss on a small position and a serious one on a large position. Margin links the two: the broker holds part of your deposit against each open trade, and a larger position uses more of it. Leverage and margin explained sets out how that works before you decide on a size.

Members who trade data often set size before the release, not after, so that a surprise does not force a decision in the middle of a fast move. The useful question is how much of the account you are willing to put at risk on one event, and whether that limit is written down before the release is published. How to trade the news covers planning around scheduled releases, including what to decide before the event.

We would like to hear your method:

• Do you reduce size before a release, or keep the same size and accept the risk?
• How do you calculate the amount you are willing to lose on one release?
• Which figure do you check first before you size a trade on a data day?
• What is the most useful rule you have for size around scheduled news?

Please share your own approach and reasoning, not calls for others to copy. Posts that promise a direction or sell signals will be removed.