The Surface Transportation Board moved last week to restart what was effectively stalled. On August 18, 2026, the STB adopted a procedural schedule for the Union Pacific and Norfolk Southern revised merger application and removed the proceeding from abeyance. Traders hoping for a faster resolution did not get one. The schedule sets up final briefs for May 28, 2027, and the STB must issue a final decision within 90 days after the record closes, putting any ruling in the second half of 2027 at the earliest.
Here is the calendar every arb desk now owns:
- Aug. 28, 2026: UP and NS must refile certain workpapers without screening or filtering criteria so regulators can review complete datasets.
- Sept. 4, 2026: Those interested in participating in the review must state their intent.
- Nov. 18, 2026: Comments, protests, and requests for conditions are due. This is the session’s first hard catalyst.
- Dec. 3, 2026: Preliminary DOJ and USDOT comments are due.
- Feb. 16, 2027: Responses to comments, protests, and requests for conditions are due.
- May 28, 2027: Final briefs on the merger are due.
- H2 2027: The STB must issue a final ruling within 90 days after the record closes, and the record close date is still TBD. That makes a decision most likely in the second half of 2027.
One complication: a final decision would not be issued if the required environmental review were not yet complete. That is a secondary risk traders tend to underweight.
The Spread and the Break Fee
The $85 billion merger agreement includes a $2.5 billion reverse termination fee. The spread math reflects that tension. Norfolk Southern’s share price sits about 5% below the $320 deal price, leaving limited upside but significant downside if the STB blocks the merger. For arb players, you are collecting carry on a position that now has a confirmed closing window no earlier than the second half of 2027, with the deal agreement set to expire January 28, 2028, but providing for automatic extensions on STB-driven delays.
The opposition is organized and well-funded. Competing companies BNSF Railway, CSX, Reading Blue Mountain and Northern Railroad, and industry organizations including the Freight Rail Customer Alliance and the National Grain and Feed Association have pushed the STB to use the full time allowed under the agency’s procedural rules for a major merger review. When your primary opponents are asking for maximum delay and citing statutory authority, they are not posturing.
CSX as the Residual Read
CSX (CSX) is trading as a direct read on the deal’s outcome, and the position is not passive. CSX launched a public resource at csxstayingontrack.com to support shippers and other stakeholders interested in engaging with the STB’s review. CSX warns the proposed combination would create a single transcontinental carrier plus four regional carriers, which it says would reduce routing options and competitive choices for shippers. That is an active lobbying posture dressed in stakeholder language.
If the deal closes on current terms, CSX loses its structural duopoly position in Eastern freight and faces a transcontinental competitor with a 50,000-mile network. If the STB blocks or demands heavy divestitures, CSX’s competitive position stabilizes and potential consolidation speculation likely returns. Activist pressure on CSX from Ancora confirms this is a sector reorganization story, not a single-stock event.
What to Watch
November 18 is the first real information event. The volume and character of the protests filed that day, particularly whether DOJ files formal objections alongside shipper groups, will tell traders more about STB sentiment than anything either railroad says publicly. Watch NSC’s spread relative to UNP’s standalone price action into that date. Any widening above current levels signals the market pricing additional approval risk. CSX moves inversely on the same catalyst.
