Abstract: The Supreme Court recently held that in reverse-payment settlements of drug patent disputes, anticompetitive effects can be inferred if the reverse payment exceeds the patent holder’s anticipated litigation costs, absent some offsetting justification. Application of this standard is problematic because defendants usually: (1) obscure the amount of the reverse payment; and (2) claim their settlement was justified by risk aversion. Further, even if a net reverse payment can be proven, it is little help in estimating the period of delay or damages. This Essay offers another type of evidence that demonstrates and quantifies anticompetitive effects. An otherwise unexplained bump in the patent holder’s stock price shows that the settlement created new future profits by extending the period without generic competition beyond what the stock market expected. The stock market test has several advantages: it rebuts the risk aversion claim (which cannot explain the stock price rise); it more effectively (though still conservatively) captures damages than the magnitude of the reverse payment; and, finally, it relies on the behavior of objective traders rather than deal makers with well-understood incentives to obscure the presence of a payment. We conduct a stock market event study on one of the early instances of a reverse-payment settlement to illustrate how the method works.