Short bets at the market's Sept. 20 peak paid off in October, as equities significantly sold off during the month. Among the 100 largest U.S. companies, the 10 with the highest short-interest ratios, or the ratio of short shares outstanding to their average 10-day trading volume, fell an average 7%. Short positions against American International Group performed the best out of the group, while those against Walgreens didn't decline as hoped.
Across the 10 largest U.S. companies, the average short-interest ratio was less than one-third of that of the group above. Amazon's SIR was 0.94 as of Sept. 20 and fell 17.8% from that point through the end of October. One notable observation, and a nod to Amazon's ubiquitous presence in the retail space, is that as of Sept. 20, its SIR was 85% lower than Target's and 83% lower than Walmart's.
