University Professor, Penn Law & Wharton. Comments occasionally on antitrust issues and follows news, public law, economics, and legal history. See my substack "The Monopoly Problem" https://herbhovenkamp.substack.com/https://bsky.app/profile/sherman1890.bsky.socialhttps://bsky.app/profile/sherman1890.bsky.social/post/3mu4taxxkxc2tNunn (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. https://nunn.law/scotus?mode=most_cited28 Aug 2026 07:21 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mu4taxxkxc2thttps://bsky.app/profile/sherman1890.bsky.social/post/3mu2nmoy3ak2vAs 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 https://herbhovenkamp.substack.com/27 Aug 2026 10:35 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mu2nmoy3ak2vhttps://bsky.app/profile/sherman1890.bsky.social/post/3mtyardqctc2zThis 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. https://herbhovenkamp.substack.com/p/innovation-shock26 Aug 2026 11:40 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mtyardqctc2zhttps://bsky.app/profile/sherman1890.bsky.social/post/3mtqwmjjnhs24“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. https://herbhovenkamp.substack.com/p/airline-joint-ventures-and-the-single23 Aug 2026 13:49 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mtqwmjjnhs24https://bsky.app/profile/sherman1890.bsky.social/post/3mtofngd7hc2cThis 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? https://herbhovenkamp.substack.com/p/antitrust-and-mergers-efficiencies22 Aug 2026 13:40 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mtofngd7hc2chttps://bsky.app/profile/sherman1890.bsky.social/post/3mtgrhnndcc2u“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. https://substack.com/home/post/p-21147340419 Aug 2026 12:51 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mtgrhnndcc2uhttps://bsky.app/profile/sherman1890.bsky.social/post/3mt57icjr3k2kmy article on antitrust's "breakup obsession" is coming out in Journal of Corp Law. This dog deserved to die a long time ago. https://papers.ssrn.com/sol3/papers.cfm?abstract_id=624365915 Aug 2026 17:35 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mt57icjr3k2khttps://bsky.app/profile/sherman1890.bsky.social/post/3mt4pgb6t4c2jMy 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. https://substack.com/home/post/p-21123910015 Aug 2026 12:47 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mt4pgb6t4c2jhttps://bsky.app/profile/sherman1890.bsky.social/post/3msxpy6lpyk2zAOC 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. https://substack.com/home/post/p-21027679613 Aug 2026 13:14 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3msxpy6lpyk2zhttps://bsky.app/profile/sherman1890.bsky.social/post/3msnlzbsgns2dThis 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. https://substack.com/home/post/p-20911884809 Aug 2026 12:37 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3msnlzbsgns2dhttps://bsky.app/profile/sherman1890.bsky.social/post/3msb3i7tkv22sThis 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. https://substack.com/home/post/p-209108172.04 Aug 2026 13:09 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3msb3i7tkv22shttps://bsky.app/profile/sherman1890.bsky.social/post/3mruiagazmk26This 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. https://substack.com/home/post/p-20908568330 Jul 2026 12:52 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mruiagazmk26https://bsky.app/profile/sherman1890.bsky.social/post/3mrshrraso22aAfter 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. https://assets.alm.com/01/1b/9c698b594e9ca455a3da444dacc2/003015365160.pdf29 Jul 2026 17:39 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mrshrraso22ahttps://bsky.app/profile/sherman1890.bsky.social/post/3mrs3cxb5d22wMy 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. https://substack.com/home/post/p-20669347929 Jul 2026 13:56 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mrs3cxb5d22whttps://bsky.app/profile/sherman1890.bsky.social/post/3mrcuy5kumc2cMy 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. https://substack.com/home/post/p-20672770423 Jul 2026 12:52 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mrcuy5kumc2chttps://bsky.app/profile/sherman1890.bsky.social/post/3mr7zhwtwlc2vMy new piece in Promarket examines the relationship among the proposed American Innovation Choice Online Act (AICOA), revised, antitrust law, and industrial policy. https://www.promarket.org/2026/07/21/aicoa-ii-is-americas-reverse-industrial-policy-initiative/22 Jul 2026 09:35 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mr7zhwtwlc2vhttps://bsky.app/profile/sherman1890.bsky.social/post/3mr6zgi55wk2cThis is why university faculty have been moving away from GOP. The movement has been by GOP [contains quote post or other embedded content]22 Jul 2026 00:01 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mr6zgi55wk2chttps://bsky.app/profile/sherman1890.bsky.social/post/3mr5r5ikcok2cThis 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. https://substack.com/home/post/p-20790181121 Jul 2026 12:01 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mr5r5ikcok2chttps://bsky.app/profile/sherman1890.bsky.social/post/3mr2xijztlk2aProminent 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 https://econantitrustguide.com/20 Jul 2026 09:16 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mr2xijztlk2ahttps://bsky.app/profile/sherman1890.bsky.social/post/3mqrb4owczs2wThe third of my 3-part discussion of the Robinson-Patman Act in "The Monopoly Problem" considers possibilities for reform. Subscription is free. https://substack.com/home/post/p-20646848316 Jul 2026 12:42 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mqrb4owczs2whttps://bsky.app/profile/sherman1890.bsky.social/post/3mqeqmrncqc2fThis 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. https://herbhovenkamp.substack.com/p/how-does-the-robinson-patman-act11 Jul 2026 13:15 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mqeqmrncqc2fhttps://bsky.app/profile/sherman1890.bsky.social/post/3mptmfqellk2xThis 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. https://substack.com/home/post/p-20283154604 Jul 2026 17:44 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mptmfqellk2xhttps://bsky.app/profile/sherman1890.bsky.social/post/3mpm2hrc6fs2xMy 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. https://substack.com/home/post/p-20425459301 Jul 2026 17:34 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mpm2hrc6fs2xhttps://bsky.app/profile/sherman1890.bsky.social/post/3mpiuyea74k2iI 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. https://substack.com/home/post/p-20408703230 Jun 2026 11:18 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mpiuyea74k2ihttps://bsky.app/profile/sherman1890.bsky.social/post/3mpiiwghi4s22Posting 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 https://substack.com/@herbhovenkamp30 Jun 2026 07:42 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mpiiwghi4s22https://bsky.app/profile/sherman1890.bsky.social/post/3mpg7q4mkq22etomorrow (June 30) I will be posting on whether antitrust law's rule of reason violates the rule of law. Subscriptions to my substack, "The Monopoly Problem," are free: substack.com/@herbhovenkamp. https://substack.com/@herbhovenkamp29 Jun 2026 09:52 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mpg7q4mkq22ehttps://bsky.app/profile/sherman1890.bsky.social/post/3mpbc27hnnc2mThis new post in “The Monopoly Problem” shows that market concentration remains important to antitrust policy, but not as important as hard core structuralists once imagined. Subscribe for free: https://substack.com/home/post/p-20275601627 Jun 2026 10:51 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mpbc27hnnc2mhttps://bsky.app/profile/sherman1890.bsky.social/post/3mozxxe7nz22zMy first of two posts on market concentration and its link to bad results examines how U.S. antitrust policy came to be concerned about it. Subscription is free: https://substack.com/home/post/p-20270967524 Jun 2026 13:01 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mozxxe7nz22zhttps://bsky.app/profile/sherman1890.bsky.social/post/3mousxckcws2yHere is my new paper commemorating the 50th anniversary of Hart-Scott-Rodino (HSR) pre-merger notification, which was intended to be enforcement neutral, and assessing its effectiveness. Comments welcome. https://papers.ssrn.com/sol3/papers.cfm?abstract_id=697705822 Jun 2026 11:49 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mousxckcws2yhttps://bsky.app/profile/sherman1890.bsky.social/post/3mounnayvdk2ealthough "market failure" is defined so broadly as to be practically useless. Nearly NO markets provide as much of things as someone might want.. [contains quote post or other embedded content]22 Jun 2026 10:13 +0000at://did:plc:5omrydccecgnknch6zmbmasc/app.bsky.feed.post/3mounnayvdk2e