Outdated legal precedent and the increasing complexity of corporate pricing tactics are handicapping regulators' and private-sector plaintiffs' efforts to prove predatory pricing—the pricing of goods or services at such a low level that other suppliers can't compete and are forced out of the market.

While the subject may sound academic, it has sweeping real-world implications as businesses seek to build online platforms to a scale that no rival could match, while also positioning those platforms as the essential infrastructure through which other firms sell their goods and services, according to participants in a three-hour Federal Trade Commission workshop Wednesday titled "Competition Snuffed Out: How Predatory Pricing Harms Competition, Consumers and Innovation."