What Happened When the CME Went Down? A Look at the First Hour in Corn and Soybean Futures

On the evening of November 27, 2025, the CME’s electronic trading system had a major outage. Trading in corn and soybean futures stopped and then came back before the market opened the next morning. Many farmers and merchandisers wondered whether the first hour after the market reopened looked normal or if it showed signs of stress.This article uses one-minute price and volume data to describe what happened during the first hour of trading on Friday, November 28, 2025.

To understand whether the morning after the outage was unusual, I compared one-minute futures data for the first hour (after the 8:30 a.m. Central Time open) on November 28 against similar data for two simple benchmarks: (i) the previous ten trading days in 2025, and (ii) all trading days in 2025. For each comparison, I looked at how much futures contract prices moved minute-to-minute and how many contracts traded in that hour. For each day, I focused on the main contract with the most trading volume during the daytime session.

For corn, the first hour after the CME came back was far from normal. Table1 summarizes how large the first hour was compared with a typical morning. Compared with the previous ten trading days, the amount of price movement was a little more than five times larger than usual, and the total up-and-down movement over the hour was more than three times larger. Trading volume during that first hour was almost nine times the recent ten-day norm. Even when compared with all trading days in 2025, corn still shows very large numbers: more than three times the usual price movement and about ten times the usual first-hour volume. These findings match what many people felt in real time. The market did not simply return to normal after the outage. Corn, in particular, showed the kind of price swings and volume that look more like a stress event than a routine morning. Soybeans also showed more activity than usual, but the increase was not as dramatic as in corn. Compared with the previous ten trading days, soybean price movement was a little under three times the recent median, and volume was just under three times. Against the full 2025 distribution, soybean price movement was a little more than four times the median, and volume was about five times. Soybeans were active, but they did not spike as sharply as corn.

For farmers, merchandisers, and elevators, there are a few practical lessons when a technical problem occurs the night before the market opens. The first hour can be the most unstable time of the day when orders that could not be processed during the outage may all come in at once when trading resumes. That argues for extra caution with large orders right at or just after the open on such days. 

Finally, this type of simple analysis, checking how big the first hour is compared with recent days and the full year, can be a useful monitoring tool. Co-ops and elevators could use similar checks to decide when to widen quotes, slow down hedging, or adjust risk limits when the market appears unusually active.

Table 1: How Big Was the First Hour After the CME Outage?

* “First-hour price movement” measures how much prices bounced around minute-to-minute in the first 60 minutes.
** “First-hour total price movement” adds up all the ups and downs during that hour.

^[1] Eunchun Park is an Assistant Professor in the Department of Agricultural Economics and Agribusiness / Fryar Price Risk Management Center of Excellence at the University of Arkansas