May 22, 2024

May 22, 2024

It’s 3:58 p.m. Do You Know Where the Volume Trades?

Saving the Best Liquidity for Last: How IEX’s Market Share Spikes in the Final Minutes of Trading

Source: IEX Market Data, NYSE TAQ Data

IEX Exchange (IEX) stands out in several ways as compared to the other 15 US stock exchanges. In this post, we’re focusing on IEX's intraday market share curve.

IEX's market share is relatively lower in the morning when a higher percentage of volume trades off-exchange. As the day goes on, IEX's market share grows, but spikes higher in the last 30 minutes before the close. Around 3:58 p.m., IEX’s market share peaks, only to fall in the final seconds of the continuous trading session before the 4 p.m. close.

Here’s two key reasons why we think this is important:

1.   IEX’s end-of-day ramp mirrors overall market volume surge, as the final minutes of the day are also when the most volume trades market wide. Not only does IEX do more trading in the final minutes, but IEX captures a higher percentage of that increased volume. The urgency to trade as the clock approaches 4 p.m. makes IEX’s higher market share extra valuable in this short window of time.

2.   IEX is unique in that a majority of our volume is non-displayed. While most non-displayed trading takes place off-exchange, off-exchange market share plummets from ~45% for most of the day to less than 30% in the final minutes. This makes quality non-displayed trades even harder to come by. In contrast, IEX’s non-displayed trading peaks in the final minutes of the day, making IEX a uniquely valuable source of non-displayed liquidity.


We’ve worked with many firms to help optimize their tactics around sourcing liquidity on IEX in the final moments of the trading day. Contact your IEX coverage to learn more.