Institutional vs Retail Trading Volume: Who Really Moves the Market

Intro

Institutional vs retail trading volume is one of those phrases people throw around like it is a clean statistic. It is not. Most “retail” flow is identified indirectly through where it gets executed (often off-exchange via wholesalers), while institutional flow can show up across exchanges, dark pools, and algorithms that slice orders into small prints. Regulators even describe off-exchange activity as only a partial proxy for retail because it is not a perfect label.
So the real question is: what proxy are you using, and what decision are you trying to make?

Tables + Analysis

Table 1: Where U.S. equity volume is executed (June 2025 example)

Source: MEMX “Retail Trading Insights” market-share breakdown by venue category.

How to use this: If you are trying to separate institutional vs retail, start with venue. Retail is disproportionately routed to wholesalers, so the 34% bucket is the cleanest public proxy in this breakdown. Institutions can still trade off-exchange (especially through ATSs), so you should not treat “off-exchange” as “retail-only.” This table is about where trading happens, not a perfect participant label.

Table 2: Estimated retail share of daily equity trading volume

Source: MEMX estimate and related retail indicators.

Decision takeaway: When someone says “retail is 30%,” they are usually referencing estimates like this, not a census. For trading decisions, the useful move is to treat retail share as a regime indicator:

• Higher retail share often means more momentum chasing and faster sentiment swings
• Lower retail share can mean institutions are setting the tone through steadier allocation flows

For context on how retail investors actually perform in the market, see our analysis of what percent of retail investors beat the S&P 500.

Table 3: Why “odd-lot volume” can fool you

Source: MEMX discussion of odd-lot share and why it is not a good retail gauge.

How to use this: Odd-lots tell you about trade size behavior, not who is behind it. If you are comparing institutional vs retail trading volume, do not build your whole conclusion on odd-lot counts. Pair it with venue data (Table 1) and retail-share estimates (Table 2).

Table 4: Flow context: retail activity vs institutional positioning

Sources: MarketWatch on H1 2025 retail trading totals and inflows, and S&P Global Market Intelligence on 2024 institutional net selling.

Decision takeaway: Volume and flows are not the same thing. Retail can account for a large slice of daily trading volume while institutions still dominate ownership and long-term allocation decisions. If you are building a “who’s in control” view, track both:

• Volume proxies (venue share, wholesaler share)
• Flow trends (net buying vs net selling)

For a global perspective on retail investor activity, see our breakdown of retail investor participation by country.

Conclusion / Callout

The cleanest way to think about institutional vs retail trading volume is: retail is easier to approximate by where orders get executed (wholesalers), while institutions show up across exchanges and ATSs, often with algorithms that hide intent. If you are using this data to trade, stop chasing a single “retail share” number and focus on what changes your decisions: venue mix, rising off-exchange share, and whether flows show net buying or net selling pressure.