I will be on a panel Sep. 15 to talk about the much maligned Philadelphia Bank merger decision: does it continue to make a worthwhile contribution to antitrust merger policy? fedsoc.org/events/revis...

Revisiting Philadelphia National Bank: The Structural Presumption and the Future of Merger Review

The 1963 Supreme Court case United States v. Philadelphia National Bank established a "structural pr...

fedsoc.org

This morning’s post in “The Monopoly Problem” considers the “Brown Shoe factors” for antitrust market definition, which the 2023 Merger Guidelines revitalized. Was that an advance or a costly mistake? herbhovenkamp.substack.com/p/antitrust-...

Antitrust Market Definition: the “Brown Shoe Factors”

The Supreme Court’s Erroneous Guidance on Market Definition Should be Overruled

herbhovenkamp.substack.com

@ProfSchrepel and I just posted a revised (Sep. 1, 2026) version of our paper on algorithmic price fixing via cartel management services. Still in press, so comments welcome. papers.ssrn.com/sol3/papers....

here is a non-paywalled copy of my new ABA Antitrust piece on Antitrust Remedies for Tech Monopoly. Short and to the point. papers.ssrn.com/sol3/papers....

This morning’s post in “The Monopoly Problem” is the first in a series about why market power is important in antitrust law and how it is measured. Next up: the "Brown Shoe" factors for market definition. herbhovenkamp.substack.com/p/market-pow...

Market Power and Market Share in Antitrust Cases

What is Market Power and Why is it Important?

herbhovenkamp.substack.com

Nunn (2026) says Antitrust Law is 17th most cited scholarly work at the S.Ct, 4X as many as Bork's Antitrust Paradox; one below Farrand's Constitutional Convention. Blackstone's commentaries is #1. The list is sortable by date, subject matter, author. nunn.law/scotus?mode=...

Scholarship at the Supreme Court

A complete database of legal scholarship cited by the Supreme Court of the United States.

nunn.law

As school is starting up again please think about my free substack "The Monopoly Problem," discussing important developments in antitrust, its movements, metrics and rules, as well as its weaknesses and errors. herbhovenkamp.substack.com

The Monopoly Problem | Substack

Covering all aspects of Antitrust Law, including its substance, procedures, and goals. Click to read The Monopoly Problem, a Substack publication with hundreds of subscribers.

herbhovenkamp.substack.com

This morning in “The Monopoly Problem:” does antitrust have any role in the anxiety that results from rapid technological change, including the rise of extremist views and populist overreactions. herbhovenkamp.substack.com/p/innovation...

Innovation Shock

Technostress Should Not Distort Antitrust Policy

herbhovenkamp.substack.com

“The Monopoly Problem” this morning posts about the Delta decision. While antitrust merger law forbids balancing gains and losses in different markets, the Transportation Department’s approach requires it and grants an antitrust immunity. herbhovenkamp.substack.com/p/airline-jo...

Airline Joint Ventures and the Single Market Rule

The Department of Transportation Must Look at a Joint Venture’s Overall Effects

herbhovenkamp.substack.com

This morning’s post in “The Monopoly Problem” considers the nature and scope of cost savings or product improvements that result from mergers; should there be an “efficiency defense” in merger cases? herbhovenkamp.substack.com/p/antitrust-...

Antitrust and Mergers: Efficient Production and Competitive Harm

Should there be an Efficiency “Defense” to Merger Challenges?

herbhovenkamp.substack.com

“The Monopoly Problem” post this morning discusses the relevance of economics to antitrust analysis, including the history of its use, questions about whether it is essential, and the type of economics that the antitrust laws employ. substack.com/home/post/p-...

THE ANTITRUST ALLIANCE WITH ECONOMICS

Is it justified? Is it Too Much?

substack.com

my article on antitrust's "breakup obsession" is coming out in Journal of Corp Law. This dog deserved to die a long time ago. papers.ssrn.com/sol3/papers....

My latest post in “The Monopoly Problem” was motivated by the 9th Circuit’s recent Surgical Instrument decision. It considers the role of behavioral economics and limitations on customer knowledge in identifying the sources of monopoly power. substack.com/home/post/p-...

Behavioral Economics and Antitrust

The Meaning and Limits of the Kodak doctrine

substack.com

AOC recently responded to an Apple price increase announcement by saying it must be broken up. This morning’s “Monopoly Problem” contribution examines the problematic issue of when a monopolist should be broken up because of its antitrust violations. substack.com/home/post/p-...

The Rhetoric and Reality of Antitrust Breakups

Monopoly Breakups Rarely Work, Especially in Digital Markets

substack.com

This morning’s “Monopoly Problem” post considers one Supreme Court attempt to simplify merger litigation: the “Philadelphia Bank Presumption” -- a merger creating a firm whose market share exceeds 30% is unlawful. It’s not perfect but has some virtues. substack.com/home/post/p-...

Is Antitrust Merger Analysis Too Compex?, Part II

The Philadelphia Bank Presumption

substack.com

This morning’s “Monopoly Problem” post inquires whether antitrust analysis of mergers has become too complex, considers market concentration as a merger metric, and examines how the Brown Shoe decision used it. substack.com/home/post/p-....

Is Antitrust Merger Analysis Too Complex? Part I

Merger Law has a TMI Problem. Simplifying Rules Essential

substack.com

This morning my “The Monopoly Problem” substack posted about a promising new appellate decision on anticompetitive algorithmic pricing. The decision creates a conflict in the federal circuit courts, which may motivate the Supreme Court to review it. substack.com/home/post/p-...

A Promising Decision on Algorithmic Price Fixing

And a Circuit Split; Is Supreme Court Review Likely?

substack.com

After my July 29 post on algorithmic price fixing in "The Monopoly Problem" the 3d Circuit issued a very promising decision on pricing software used by Caesar's, Harrah's, Tropicana and other Atlantic City hotel-casinos. I'll post more about it tomorrow. assets.alm.com/01/1b/9c698b...

My morning article in “The Monopoly Problem” examines the messy, unproductive way that the courts have been handling cases that involve algorithmic price fixing. It does not have to be as hard as they make it. substack.com/home/post/p-...

Algorithmic Price Fixing

Antitrust Law’s Agreement Requirement and the Role of Human Actors

substack.com

My substack, “the monopoly problem,” just posted a piece on antitrust and vertical integration by ownership or contract – its promises, competitive threats, and how to assess them. substack.com/home/post/p-...

Antitrust and Vertical Integration

Why Do Firms Integrate Vertically, and When Does it Harm Competition?

substack.com

My new piece in Promarket examines the relationship among the proposed American Innovation Choice Online Act (AICOA), revised, antitrust law, and industrial policy. www.promarket.org/2026/07/21/a...

AICOA II Is America’s Reverse Industrial Policy Initiative - ProMarket

The revived American Innovation Choice Online Act singles out a handful of Big Tech giants for unique, antitrust-like restrictions, but without the standard methodological rationale of antitrust analy...

promarket.org

This is why university faculty have been moving away from GOP. The movement has been by GOP

Luke Herrine@lookheron.bsky.social · 2mo ago

This has actually been studied! www.cambridge.org/core/service...

This morning “The Monopoly Problem” includes a post on yesterday’s Paramount merger decision. Hardly the end of this case, but the state Attorneys General have some reason to be hopeful. substack.com/home/post/p-...

Is the Paramount/Warner Merger in Trouble?

This is not over, but the state AGs have reason to be hopeful.

substack.com

Prominent post-Chicago antitrust economist Steve Salop (G-Town) has performed a great service -- a guide to antitrust and modern economics -- free in .pdf or an inexpensive Amazon Paperback. You dont need much economics in order to read it. econantitrustguide.com

Modern Economic Analysis and Antitrust Law: A Guide

Free to download

econantitrustguide.com

The third of my 3-part discussion of the Robinson-Patman Act in "The Monopoly Problem" considers possibilities for reform. Subscription is free. substack.com/home/post/p-...

Reforming the Robinson-Patman Act

Can it be Fixed, or is Repeal the Best Solution?

substack.com

This morning my substack “The Monopoly Problem” posted the second in a series – “How Does the Robinson-Patman Act Work? A third post, in a few days, discusses reform possibilities. herbhovenkamp.substack.com/p/how-does-t...

How Does the Robinson-Patman Act Work?

Part 2 in a series on the Robinson-Patman Act

herbhovenkamp.substack.com

This post in The Monopoly Problem, "The Salesman, the Housewife, and the Campaign Against Low Prices," is part of a 3-part series on the Robinson-Patman Act. Coming next: how the RPA works, and then, whether it can be reformed. substack.com/home/post/p-...

The Salesman, the Housewife, and the Campaign Against Low Prices

A Prehistory of the Robinson-Patman Act

substack.com

My new post in “The Monopoly Problem” frets about Trump v. Slaughter as a threat to FTC independence, and wonders what the Agency will look like now and how it can be fixed. substack.com/home/post/p-...

The Future of a Less Independent Federal Trade Commission

What Trump v. Slaughter Says About Independent Regulatory Agencies

substack.com

I argue in “The Monopoly Problem” that antitrust’s rule of reason is not so open ended that it violates the rule of law, but only if the courts keep it within its intended boundaries. substack.com/home/post/p-...

Does Antitrust’s Rule of Reason Violate the Rule of Law?

Answer: It Depends on What You Expect Antitrust to Accomplish

substack.com

Posting from Scotland, so sorry about the hour. Here I argue in “The Monopoly Problem” that antitrust’s rule of reason is not so open ended that it violates the rule of law, provided that the courts keep it within its intended boundaries. substack.com/@herbhovenkamp

The Monopoly Problem | Substack

Professor, University of Pennsylvania Law School and the Wharton School; frequent contributor on antitrust law and legal and business history.

substack.com