Half of all US stock trading volume is in 93 names

There are roughly twelve thousand US symbols that trade on an ordinary day. On a median session in our data, 93 of them account for half of all the money that changes hands. That is 0.77% of the names. Everything else shares the remaining half of US trading volume, and the bottom half of all names, around six thousand of them, together account for 0.151% of dollar volume.

1. How concentrated, exactly

We ranked every symbol by dollar volume on each of 181 sessions and measured how much of the day's total the top names held. Ten names take more than a fifth of the day. A hundred take half. By a thousand you have seven eighths of all the money, and there are still more than ten thousand names left to share the rest. The number of names needed to reach half has a median of 93, with quartiles of 83 and 102.

2. It barely changes from day to day

The quartiles are the part worth noticing. The share held by the top 100 moves between 49.8% and 52.8% across the middle half of sessions. That is not a feature of quiet days or busy days; it is a property of the market, and it holds whether total dollar volume is high or low. Markets feel like they rotate. Leadership changes, sectors come in and out of favour, the names on the gainers list are different every morning. None of that moves the concentration. Whatever is leading on a given day, roughly the same slice of names carries the money.

3. Who is at the top

The names that sat in the top 10 by dollar volume most often: Three names were in the top 10 on every single session: two index funds and one stock. Two of the ever-present names, SPY and QQQ, are not companies at all but baskets of them, which means a large part of the concentration is investors buying the whole market through a handful of wrappers rather than choosing individual names.

4. Why it matters if you trade individual names

The concentration is a map of where liquidity lives, and it runs almost exactly opposite to where attention goes. The names that dominate a gainers screen are almost never among the names carrying the money. We checked: of the 30 biggest open-to-close gainers on each session, the median number that were also in the top 100 by dollar volume was 0. On 73.9% of sessions there were none at all, and the most on any single session was 2. They live in the long tail, the part of the market that shares the thinner half of the money. That is not a problem in itself, but it changes what a trade in those names costs and how large it can be. We measured the difference directly: the most-watched movers trade in far smaller clips than the names that carry dollar volume, in top gainers trade in $887 clips, and how that should cap a position is in how to size a day trade. The practical reading is that a liquid name and an exciting name are, most of the time, different names. A screen that ranks by percentage move will fill up with the second kind.

5. The long tail is mostly not stock

Before reading too much into the bottom half holding 0.151%, it is worth knowing what is in it. Our universe is every symbol that carried a daily bar, and a large share of those are not operating companies: exchange-traded funds that almost nobody trades, warrants, units, preferred issues and notes. Many of them print a handful of trades a day. They inflate the denominator and make the bottom half look emptier than a universe of common stock alone would. So the concentration among common stocks is somewhat less extreme than 93 names out of roughly twelve thousand suggests. The top of the distribution is unaffected, since the names carrying the money are overwhelmingly liquid funds and large companies; it is the tail that is padded. Limitations Dollar volume here is daily volume multiplied by the volume-weighted average price, which approximates the value traded but is not the sum of individual trade values. The universe includes every instrument with a daily bar and was not restricted to common stock, for the reasons in section 5. A common-stock-only version would raise the number of names needed to reach half and lower the headline share held by the top. Concentration is measured on each session independently and then summarised, so the top-10 table counts how often each name appeared, not how much it traded in total across the window. A name that dominated a few very large sessions could hold more total dollar volume than one that appeared in the top 10 more often. The window is 181 sessions, 2025-12-02 to 2026-08-21. Concentration is known to drift over years as index investing grows, and this measurement says nothing about that longer trend.