Volume and message traffic spike in wake of tariff announcement
May 9, 2025
Surge in Volumes and Message Traffic; Record Volumes on MEMX
Highlights & Recent Developments
- The tariff announcement on April 2nd brought record trading activity on MEMX’s equities and option exchanges
- Six of the top 10 volume days on MEMX Equities since 2023 occurred in April
- On April 9th, MEMX Equities traded 749 million shares and handled 1.69 billion messages
- Five of the 10 highest volume days on MEMX Options since inception occurred in April
- MEMX Options hit new daily records of 3.1 million contracts on April 4th and 15.5 billion OPRA messages on April 9th
- MEMX Options also hit new volume and market share monthly records in April
Equities Exchange Highlights
The "Liberation Day" tariff announcement on April 2nd triggered significant trading activity in the days that followed.
Looking at the 10 highest volume days on MEMX since the beginning of 2023, six of them occurred in April 2025. The most active day was April 9th, when MEMX traded 749 million shares and handled 1.685 billion messages (orders, cancels, replaces, and trades).
Figure 3 shows the most active retail stocks and ETFs on MEMX in April, including TSLA, NVDA, SPY and PLTR. Activity was generally balanced between buying and selling across these securities. Retail investors were also active in sub-$1 stocks, which accounted for 17% of industry share volume in April.
Options Exchange Highlights
MEMX Options hit new volume and market share records in April. MEMX Options average daily contracts increased 176% year-over-year to 1.99 million contracts. MEMX Options total market share was 3.73% and regular electronic market share was 6.54%. Similar to equities, the "Liberation Day" tariff announcement on April 2nd triggered a surge in options trading activity.
Five of the 10 highest volume days on MEMX Options occurred in April. The highest volume day was April 4th, when MEMX traded 3.1 million contracts and handled 11.7 billion OPRA SIP messages.
The growth in options messages traffic continues to challenge the industry. Industry OPRA SIP average daily messages increased 39% year-over-year to 234 billion in April. This only reflects top-of-book messages, not depth-of-book activity on exchange proprietary feeds. MEMX’s average daily messages on the OPRA SIP increased 50% year-over-year to 10.3 billion in April.
In April, the most active retail options contracts included SPY, QQQ, NVDA and TSLA. Not surprisingly, there is an overall overlap between the most active symbols traded in equities and options by retail investors.
