In the case of A. B. Small Company v. American Sugar Refining Company, 1924, the U.S Supreme Court ruled in favor of the defendant, American Sugar Refining Company (ASRC). The plaintiff, A.B Small Co., accused ASRC of violating antitrust laws by selling sugar below cost to drive competitors out of business and create a monopoly. However, it was found that there were no federal or state laws prohibiting such practices at that time; therefore ASRC's actions were not illegal under existing law. The court also noted that while predatory pricing could potentially harm competition and consumers in certain circumstances if it led to monopolization or attempted monopolization - this was not proven in this particular case as other factors like war conditions had influenced sugar prices during the period concerned. This ruling set an important precedent for future cases involving alleged anti-competitive behavior: proving intent alone is insufficient; actual harmful effects on competition must be demonstrated.

In the dissenting opinion for A. B. Small Company v. American Sugar Refining Company, Justice Holmes argued that the majority's decision was inconsistent with previous rulings and undermined Congress' power to regulate commerce under the Constitution. He contended that a violation of an act of Congress is not automatically a tort unless it causes harm or damage to another party, which he believed wasn't proven in this case. Furthermore, he disagreed with the majority's interpretation of "unfair competition," arguing that it should be limited to deceptive practices rather than expanded to include any violation of federal law as per their ruling in this case.