Data-driven technology companies are challenging classical definitions of antitrust law all over the globe. This paper will argue that data accumulation and the market power such data yields, both in current and future markets, should be a key consideration within American antitrust law and regulation. By analyzing the European Commission’s decision on the Facebook/WhatsApp merger, I will demonstrate how the current principles that guide antitrust analysis—particularly, narrow market definitions and price-theory based consumer welfare standards—struggle when applied to such data-driven technology companies (DDTCs) with market-fluid natures and non-traditional, data-driven revenue models. To conclude, I propose that consumer welfare and economic choice in DDTC mergers would be best served by regulators including a cross-sector “Data Market” consideration in their regular market analysis to capture the competitive impact that data accumulation resulting from a merger can have on current and future consumer choice in the market.