How the American takeover of a French national champion became intertwined in a corruption investigation

OVER THE past decade, American legal and regulatory authorities have subjected scores of large foreign companies to extraterritorial actions. Paying large fines, which can exceed $1bn, has often been the only way finally to settle such accusations of serious misconduct—typically, corruption or breaching sanctions—outside America. As a result, many bosses and executives are quietly paranoid about the long arm of American sheriffs.

Such cases, however, rarely go to trial, and the firms involved are limited in what they can say about them; surprisingly little is known about how the process works. The Economist has identified an exception: Alstom, a French power and transport group that faced an American legal action in 2010-15 and which sold the bulk of its assets to General Electric (GE) in a deal that was announced in 2014 and closed in late 2015.

The case of Alstom and GE is important for three reasons. First,...