Three years after much-heralded changes to the United Kingdom’s Bribery Act took effect, the U.K. government has secured just three convictions under the revised act. None of the cases involved instances of far-reaching corporate corruption: The convicted individuals are a court clerk who took bribes to expunge drivers’ records, a cab driver who attempted to bribe a cab licensing official and a Chinese student who tried to pay his teachers to give him a passing grade.

Yet attorneys at Am Law 200 and U.K. firms say that the Bribery Act has had a significant impact on companies operating both in and outside the United Kingdom. At least two major corporations, pharma giant GlaxoSmithKline plc and automaker Rolls-Royce Holdings plc, are under investigation for suspected violations of the Bribery Act, and the act has spurred other companies to step up their compliance efforts.