70 percent of U.S. hospitals belong to chains. HCA led the merger wave. Here is the data.

In Charlotte, North Carolina, every major hospital is operated by Atrium Health, the regional system formed when Carolinas HealthCare System and Wake Forest Baptist merged in 2018 [3]. A patient in Charlotte who needs an emergency room, an MRI, or a cardiology consult has, in practical terms, one provider to choose from. Charlotte is not unusual. In dozens of metropolitan markets across the United States, a single hospital system now controls a majority of the inpatient beds [3]. The merger documents that produced those markets promised lower costs and better coordination. Two decades of MedPAC, AHRQ, and Health Affairs analysis tells a different story: prices rose, margins widened, quality moved sideways [1][2][4].

In 1998, the United States had roughly 5,800 community hospitals, the great majority of them either standalone facilities or members of small regional groups [6]. By 2024, the same number of hospitals existed, but more than 70 percent of them belonged to one of fewer than 200 multi-hospital systems [6]. The hospitals that remained independent had become the exception. The systems that absorbed them had become the structural norm of American healthcare delivery.

The merger wave that produced this concentration ran on a specific argument. Health systems combining with other health systems, the case went, would generate efficiencies, reduce duplicative administrative costs, share technology investments, negotiate better terms with insurers and suppliers, and pass the savings to patients in the form of lower prices and improved care. The Federal Trade Commission, the Department of Justice, and state attorneys general approved the great majority of the proposed mergers. The argument was the basis on which the approvals rested.

The data accumulated since the consolidation wave does not support the argument as advertised [3].

The Official Story

The hospital industry’s stated rationale for consolidation centered on three claims. First, that scale would let combined systems negotiate lower drug, supply, and labor costs and pass those savings on. Second, that combined systems could invest in expensive technology, electronic health records, advanced imaging, surgical robotics, that smaller hospitals could not afford on their own. Third, that combined systems could coordinate care across facilities in ways that would improve outcomes and reduce avoidable hospitalizations.

The American Hospital Association articulated each of these arguments in regulatory filings, congressional testimony, and public commentary across the consolidation period [6]. The arguments were not unique to any one merger. They were the standard frame.

Follow the Money

The financial mechanics that played out across the merger wave worked in three layers.

First, hospital prices charged to commercial insurers rose substantially in markets that consolidated, in some cases by 20 percent or more relative to comparable non-consolidating markets, according to the Cooper et al. analysis published in Health Affairs in 2019 [4]. The price increases concentrated in markets where the post-merger system held a dominant share of the local hospital beds.

Second, hospital operating margins on commercial-insurer business widened across the same period [1]. MedPAC’s annual reports document the gap between Medicare margins, which are generally negative or near zero, and commercial-insurer margins, which have run consistently above 10 percent for the largest systems [1]. The gap is the financial signal that consolidation produced. Commercial insurers, lacking alternative hospitals to direct patients toward in concentrated markets, paid the rates the dominant systems demanded.

Third, the savings the merger arguments promised, lower drug and supply costs flowing through to patients, did not appear in the AHRQ data on per-admission costs, in the KFF analyses of out-of-pocket patient spending, or in the Health Affairs studies of post-merger price trends [2][3][4]. The internal cost reductions, where they occurred, were retained as margin rather than passed through.

The Network

The largest hospital systems in the United States now each control bed counts that exceed those of the entire hospital systems of small European countries. HCA Healthcare, the largest investor-owned chain, operates more than 180 hospitals across multiple states [6]. CommonSpirit Health, formed by the 2019 merger of Catholic Health Initiatives and Dignity Health, operates more than 140 [6]. Ascension, Trinity Health, and AdventHealth each operate more than 90 [6]. Several large nonprofit systems, including Mass General Brigham, NewYork-Presbyterian, and Northwestern Memorial HealthCare, dominate their regional markets even without national bed counts.

The structural feature that connects these systems is not their ownership form, investor-owned versus nonprofit versus religious-affiliated. It is the share of regional hospital capacity each holds within its primary geographic markets. In dozens of metropolitan areas across the United States, a single hospital system now controls a majority of the inpatient beds [3]. In those markets, the system’s pricing decisions are not constrained by competition because there is no competition.

What Was Buried

The FTC’s 2017 challenge to the Advocate-NorthShore merger in the Chicago metropolitan area produced a public record of how consolidation analysis works in practice [5]. The FTC’s economic experts argued, and a federal court agreed, that the merger would create a system holding more than 50 percent of acute-care beds in the relevant geographic market [5] and would produce price increases for commercial insurers and ultimately for the patients those insurers covered. The merger was blocked. The economic analysis used to block it relied on the same kind of evidence that, in many other cases, the agencies have not pursued or have lost in court.

Most proposed hospital mergers have been approved [3]. The cases that produce blocking orders represent a small minority of the consolidation activity. The cases that do not produce blocking orders are the cases that produced the consolidation pattern visible in the AHA bed-count data [6].

The Stakes Now

Federal antitrust enforcement against hospital mergers has tightened modestly since 2020, with the FTC and DOJ issuing updated merger guidelines in 2023 that explicitly addressed health-care concentration [3]. State-level enforcement has intensified in several jurisdictions, with Connecticut, Oregon, and California adopting market-oversight statutes that subject hospital mergers to additional review. The volume of merger activity has slowed, but the consolidation that has already occurred is largely irreversible at the antitrust-policy level. Reversing it would require divestitures, court orders, and operational separations that no agency has pursued at scale.

The structural condition the merger wave produced is therefore the operating condition of American hospital care. The same dynamic visible in the three-PBM concentration that sets U.S. prescription prices operates in hospital care, with regional systems rather than national PBMs as the consolidation actor.

The One Thing That Matters

The argument that hospital consolidation lowers costs and improves care was the basis for federal and state regulatory approval of the merger wave that produced today’s hospital landscape. The argument was testable, and it has been tested across two decades of consolidation. The MedPAC margin data, the AHRQ utilization data, the KFF cost analyses, and the Health Affairs research converge on the same finding: prices rose, margins widened, quality moved sideways, and patient out-of-pocket costs grew faster than wages [1][2][3][4].

The merger documents promised lower costs. The data showed the opposite. The structural condition the consolidation produced is durable, and the regulatory framework that allowed it has not yet adapted to the evidence.