This incipiency standard was strengthened by the 1950 #CellerKefauverAmendment.

The lawmakers who passed both acts were clear about their legislative intention - to block this kind of stealth monopoly formation. For decades, that's how the law was enforced. For example, in 1966, the DoJ blocked Von's from acquiring another grocer because the resulting merger would give Von's 7.5% of the regional market.

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