We do not keep up with all firms, but from our knowledge, we were on par with the industry (see other FCM notice below).
So now sure how to proceed with explanation, other than the margin requirements were updated due to the risk of extreme volatility. And looking back at the market moves, the increased margins matched the market conditions, so this was in our opinion the appropriate risk management action.
For example, a notice from one of the firms
@J.P. mention:
"Unnamed FCM" has been closely monitoring the status of the British European Union Referendum ("Brexit" vote) taking place on June 23, 2016. Due to anticipated increased volatility, "Unnamed FCM" deems it necessary to increase margin requirements on certain cleared futures products. As of the close of business June 20, 2016, "Unnamed FCM" will raise margin requirements to the following percentages of Exchange minimums:
Product/Group
Margin Percentage
British Pound - 200%
Euro Currency - 200%
Swiss Franc - 200%
Japanese Yen - 200%
Gold - 200%
Silver - 200%
European Interest Rates - 150%
European Equity Indexes - 150%
As of today's US open, AMP DayTrade Margins are back to normal, except the currencies.
https://news.ampfutures.com/phase-2-post-brexit-vote-results-daytrade-margins-roll-back