Is it time to redefine the middle market? RSM says it should now be $30M-$10B

The evolution of US growth companies means that defining the middle market in 2026 requires a refresh of the criteria according to new research.

The revenue threshold for RSM US LLP’s definition of the American middle market has been expanded to include firms generating between $30 million and $10 billion annually; an adjustment the firm says better reflects today’s operating reality.

The revised parameters are grounded in newly released research, which argues that legacy definitions no longer capture the scale, sophistication and economic footprint of companies that now dominate the segment.

RSM’s economics team points to structural changes ranging from rapid technology adoption to capital market evolution, that have fundamentally altered how these businesses grow and compete. Under the updated definition, the middle market now encompasses roughly 125,000 companies employing 50 million people, including a rising number of organizations that have scaled through consolidation and advanced operating models.

“RSM’s view of the middle market reflects the opportunities and challenges our clients face every day: businesses operating at greater scale, moving faster and managing risks that didn't exist a decade ago,” said Brian Becker, CEO of RSM’s transatlantic partnership and managing partner with RSM US LLP. “Our new research promotes an even deeper understanding of the dynamic, growth-oriented businesses that make up this critical segment of the US economy. These insights are key to helping middle market businesses manage the complexities of today’s rapidly evolving business environment.”

From an economic lens, outdated benchmarks risk obscuring the segment’s true influence. “Relying on definitions based on decades-old economic data means misreading the most dynamic force in the US economy,” said Joe Brusuelas, the firm’s chief economist. “Today’s middle market companies operate at greater scale, with higher fixed costs and far more exposure to global volatility. Updating how we understand this segment is critical for investors, lenders, policymakers and business leaders.”

RSM plans to reassess the definition annually, aligning it with current economic data and embedding it into tools such as the firm’s US Middle Market Business Index and future research.

A second study, based on analysis of more than 1,000 companies within the expanded middle market, highlights how consolidation, digitization and shifting capital strategies are reshaping risk profiles. Automation, cloud computing and AI-enabled processes have boosted productivity—but also introduced new layers of operational and financial complexity.

Authored by RSM Deputy Chief Economist Kevin Depew and RSM Strategic Imperatives Senior Director Scott Reamer, the report concludes that complexity itself has become a limiting factor on performance, influencing decisions from workforce planning to capital deployment.

Among the findings, sales per employee have more than doubled since 2009, largely due to automation and process upgrades. Capital expenditures are down 69%, reflecting asset-light strategies and tighter capital discipline. R&D investment has nearly tripled, signaling innovation-led growth once typical only of large enterprises. Supply chain complexity has increased nine-fold, elevating exposure to operational disruptions.

“Today’s middle market bears little resemblance to the segment described in the post-financial-crisis era,” said Reamer. “Companies today are more globally integrated and technologically enabled than ever before. These structural shifts demand a more contemporary approach to growth, risk management and value creation.”