In one of the largest oil and gas M&A actions this year, on May 7, 2026, Devon Energy (NYSE: DVN) closed its acquisition of Coterra Energy. Post-close, Devon’s market capitalization is roughly 55 billion dollars as of this writing.

Statements from the organization’s leadership strongly indicate the key stakeholders have been intentional not only about the financial and operational gains unlocked by the merger, but about the integration path itself. On this year’s second-quarter earnings call, CEO Clay Gaspar stated: “It started on day one when we closed the merger with 95% of our core IT systems and processes already decided.” Achieving that means integration teams were working diligently ahead of close to analyze and reconcile a huge number of business processes across both organizations. In an internal employee communication attached to a February 2026 SEC filing, Gaspar said: “Merger integration planning officially kicks off today. We’ve named an integration steering team and selected an external partner, McKinsey & Co., to support our integration efforts. Taking this step will set us up for success Day One post-close.”

None of this is direct evidence they’ve applied the same discipline to business processes or data specifically. But the pattern is there. Forming an internal steering team and selecting an integration partner months ahead of close shows solid foresight. Add to that a billion-dollar synergy target broken into specific categories, and an eighteen-month runway to realize that target, and the picture suggests leadership has been through this before.

Devon’s own history bears this out. Gaspar’s tenure at WPX included the 2021 Devon/WPX merger, and Cimarex’s CEO, Tom Jorden, led his company through the 2021 merger that formed Coterra, and has run the combined Coterra ever since.

None of this guarantees Devon will avoid the Day 101 Problem. But it’s exactly the kind of pattern to look for if you want to do your best to prevent it. Committing to a process and a set of checkpoints, instead of a specified go-live date that may have to change later, is what keeps timeline fantasy at bay.

If you’ve lived through a merger integration, what’s the one thing you wish the CEO had understood about day 100, not day one?

Originally posted on LinkedIn.