Antitrust Review of Financial Institution Mergers

Introduction

Every financial institution merger must pass two distinct approval tracks. Banking regulators (the Fed, FDIC, and OCC) evaluate safety, soundness, capital adequacy, management quality, and community impact under the Bank Merger Act and Bank Holding Company Act. Separately, the DOJ evaluates competitive effects under the Clayton Act and Sherman Act, with the authority to challenge mergers that substantially lessen competition regardless of what banking regulators decide. This dual-track structure makes antitrust risk a central consideration in every FIG deal, and the September 2024 policy updates significantly raised the bar for merger approval in ways that FIG bankers must understand.

On September 17, 2024, the DOJ, FDIC, and OCC released coordinated but separate policy updates that fundamentally changed how financial institution mergers are evaluated. The Federal Reserve notably did not participate, maintaining its precedent-based approach.

Banking Addendum to the 2023 Merger Guidelines

The 2024 Banking Addendum replaced the DOJ's 1995 Bank Merger Guidelines and applies the general 2023 Merger Guidelines framework (used for all industries) specifically to bank transactions. The most significant change is the presumption threshold: mergers are now presumed anticompetitive if they increase the HHI by more than 100 points (down from 200 under the 1995 guidelines) in a market where the post-merger HHI exceeds 1,800, or if the merged firm's market share exceeds 30%. The Addendum also expands the scope of competitive analysis beyond traditional deposit market share to include products and services (credit cards, mortgages, commercial loans), networks and platforms (payment systems, digital banking), distinct customer groups (retail, commercial, small business), and geographic dimensions beyond traditional banking markets.

The FDIC simultaneously issued a final Statement of Policy on Bank Merger Transactions that heightened scrutiny for deals creating institutions with $100 billion or more in assets and required public hearings for mergers producing $50 billion+ institutions. However, the FDIC rescinded this policy in early 2025 under a new administration, reinstating the pre-2024 framework pending further review. This regulatory whiplash creates genuine uncertainty for deal planning.

The OCC eliminated its expedited review procedures, removing the safe harbor that had allowed smaller deals to proceed on a faster timeline. Combined with the DOJ's lower thresholds, the practical effect is that more deals face more scrutiny for longer periods.

The Herfindahl-Hirschman Index remains the primary quantitative tool for evaluating competitive effects in bank mergers. HHI is calculated as the sum of squared market shares in a defined market, with deposit share in local banking markets as the traditional input.

The Addendum's expansion beyond deposits is equally significant. Under the old framework, a bank that dominated local commercial lending but had modest deposit share might have faced no antitrust concern. Now the DOJ evaluates whether the merger reduces competition in any relevant product market, including credit cards, small business lending, wealth management, mortgage origination, and payment networks.

Not all financial institution mergers fall under the same antitrust authority. The DOJ has exclusive jurisdiction over bank mergers, but the FTC handles antitrust review for many other financial services transactions.

DOJ jurisdiction covers all bank holding company mergers, nationally chartered bank mergers, state-chartered FDIC-insured bank mergers, and savings and loan holding company mergers. The DOJ also reviews credit union-bank acquisitions (which reached a record 22 deals in 2024).

FTC jurisdiction covers insurance broker and carrier mergers, asset management consolidation, non-bank mortgage lender mergers, fintech acquisitions, and finance company transactions. The four insurance brokerage mega-deals of 2024 (totaling over $44 billion) fell under FTC review, with Gallagher's $13.5 billion AssuredPartners acquisition receiving a second request (deeper investigation) in March 2025 reflecting concerns about commercial insurance market concentration.

The Capital One-Discover merger ($35.3 billion, announced February 2024) tested the new framework's limits. The combined entity would control approximately 31% of the subprime credit card market, triggering both product market and customer segment concerns under the Addendum's expanded analytical scope. The deal faced a federal class action lawsuit challenging its antitrust legality, prolonged regulatory review, and significant public opposition. Ultimately, in April 2025, the DOJ issued a memo to banking regulators stating insufficient evidence to block the deal. The Fed and OCC granted conditional approval, and the transaction closed in May 2025 after approximately 15 months of review.

By contrast, Fifth Third's $10.9 billion acquisition of Comerica (announced 2025) is expected to proceed faster because the geographic overlap between Cincinnati-based Fifth Third and Dallas-based Comerica is minimal, reducing deposit market concentration concerns despite the deal's size.

The TD Bank-First Horizon withdrawal ($13.4 billion, terminated May 2023) is often cited as an antitrust failure, but the deal was abandoned primarily due to TD's anti-money-laundering compliance issues, not competitive concerns. TD paid $200 million in a termination fee to First Horizon.

Antitrust analysis begins before a deal is announced. FIG bankers perform pre-deal competitive assessments that map HHI impacts across every overlapping local market, identify product markets where combined share approaches 30%, and estimate the scope of potential divestiture requirements.

The deal protection toolkit includes longer outside dates (18-24 months for mega-deals, reflecting extended review timelines), reverse termination fees capped to reflect regulatory risk allocation, and regulatory condition triggers that give either party walk rights if approvals are not obtained. Preemptive divestiture packages, where the acquirer identifies branches and business lines it will sell before filing, remain the standard approach, though the DOJ's skepticism about whether branch divestitures alone address competitive concerns means FIG bankers increasingly propose business line divestitures or behavioral commitments alongside branch sales.

The current environment rewards early and frequent engagement with DOJ staff, comprehensive economic analysis of all relevant product markets (not just deposits), and realistic expectations about review timelines. Deals that would have been routine under the 1995 guidelines may now require 12-18 months of regulatory work, and FIG bankers who build this reality into their advisory approach will deliver better outcomes for clients.