In 1993, in Brooke Group, Ltd. v. Brown & Williamson Tobacco Corp., the Supreme Court has unquestionably recognized the entry barrier concept and imposed it in antitrust jurisprudence. It has not provided a clear definition of barriers to entry or clearly explained how the presence or absence of such barriers affect specific antitrust claims, though.
Some lower federal courts appear to follow ideas from economic literature that may be inconsistent with the predominant precedents. In United States v. Baker Hughes Inc. the D.C. Circuit decision rejected the government’s argument that entry must be "quick and effective" to count on the ground that this requirement overlooks that potential competition, even it never resulting in actual entry, can nevertheless exert competitive pressure on the market.
The Ninth Circuit Federal Courtin Rebel Oil, a monopolization case, recognized that entry, though easy for some firms, may be insufficient to solve a competitive problem "if the market is unable to correct itself despite the entry of small rivals" and cited the Merger Guidelines "timely, likely, and sufficient" language as persuasive authority for undertaking that analysis.
The legal question involving burdens of proof is unresolved. The 1992 US Merger Guidelines disclaim allocation of burdens; they describe an analytic framework adopted by the enforcement agencies, not a legal framework that should be employed by a court. Courts applying the Philadelphia National Bank presumption of anticompetitive effect from market concentration generally address entry as a rebuttal factor, designed to respond to the government’s showing of concentration. This approach clearly places a burden of proof on the defendant.
On the other side of the Atlantic, most European rulings on dominance are determined around the existence of additional market characteristics, which either add to or detract from potential dominance. It is said that dominant positions raise “almost insuperable practical and financial obstacles” for actual and potential competitors. These characteristics have expanded through later case law and do not form a fully defined set.
On the one hand, in Continental Can, the European Court of Justice emphasized the importance of proving the possibilities of other competitors to enter the market, before ascertaining the existence of a dominant position. In other words, the ECJ stated that a causal relationship should not necessarily exist between the dominant position and its abuse, or that the causal relationship between a dominant position and its abuse is not necessary to ascertain the abuse of the dominant position.
On the other, in Hoffmann-La Roche, it provided a caveat in listing the factors (markets shares, price elasticity of demand, profitability measurement, barriers to entry, barriers to expansion, structural factors and behavioral factors) that may determine the existence of a dominant, which taken separately however, are not necessarily determinative.
In the 2012 AstraZeneca AB and AstraZeneca plc v European Commission , the European Court of Justice (ECJ) dismissed an appeal brought by AstraZeneca against a General Court ruling upholding the Commission’s decision fining AZ 60 million euros for abuse of a dominant position on the market for proton pump inhibitors (PPIs) used for gastro-intestinal diseases. The Commission found that AZ had misused pharmaceutical marketing procedures in order to exclude competition from generic alternatives to, and parallel imports of, its Losec drug.
In Brazil, the most recent case (October 2018) involving barriers to entry was Administrative Process N. 08012.007423/2006-27 where the Tribunal of the Administrative Council for Economic Defense (Cade) condemned the ice cream maker Unilever, owner of the Kibon brand, for limiting and harming free competition by preventing access by competitors to distribution channels. The case concerned points of sale (POS) in the ice cream market in the municipalities of Rio de Janeiro and São Paulo. During the investigation, there were indications that the company would have offered discounts and bonuses to the POS in exchange for exclusive sales, merchandising (privileged exposure) or the use of refrigerators. Cade also identified the existence of contractual provisions imposing the obligation of points of sale to sell a minimum quantity of products under penalty of fine and refund of the amount advanced upon signing the contract.