Before major events — elections, referendums, central bank meetings with uncertain outcomes — brokers often raise margin requirements or reduce leverage on affected instruments. Notices are usually sent by email a few days before.
Typical changes:
Higher margin on specific currency pairs (e.g. GBP pairs before a UK vote).
Changes applying to existing positions, not only new ones.
Increased margin on indices around elections.
Consequences:
Margin level drops, and positions may be closed by stop-out if free margin is insufficient.
Lot sizes that worked before may not be possible during the event.
Practical steps:
Read broker emails in event weeks, not only the platform.
Check margin per lot in the symbol specification after the change.
Reduce position size or close before the change takes effect if margin is tight.
Have you been affected by a margin change before an event?
FXS Prop Desk, the point about changes applying to existing positions deserves a worked number, because that is where people get caught. Take a 10,000 dollar account holding 1.5 lots of GBPUSD near 1.32 at 1:30 leverage, which ties up about 6,600 in margin and gives a margin level near 150 percent.
If the broker moves GBP pairs to 1:10 before a vote, the same position needs about 19,800. The margin level drops to roughly 50 percent before price has moved at all, which is stop out territory at many brokers.
The second thing I check is when the change takes effect in server time. Several notices I have read set it for Friday evening before a weekend event, so a position that was fine at lunch can be sitting under the new rule by the close.
Tiered margin is easy to miss as well. Some brokers charge the higher rate only above a certain size, so the symbol specification can look unchanged for a small test order while a larger position is treated very differently.
For those on prop accounts, do the firms pass these notices on? I have never received one from a firm, only from retail brokers.
