By David Dorf-Oracle on Jan 30, 2015
Fraud analysts at credit card issuers (banks) pour though transactions looking for credit card fraud. Patterns in this data are what usually lead investigators to find breaches. Find a bunch of transactions involving stolen numbers, then work backwards to find the commonality and you've got your breach. But there are lots of additional patterns in that data as well.
Two enterprising fraud analysts at Capital One decided to look at purchase patterns for public retailers, then use that information to place bets in the stock market. Why not, right? All of Capital One's credit card transactions are sitting in the database for them query. As you can see in the heavily redacted SQL query below, it took some serious analytical skills.
For example, they compared this quarter's volume of Chipotle transactions to last quarter's and seeing that sales were strong decided to buy call options just before the earnings announcement. Earnings were good so the stock went up, and their $100,000 investment netted $270,000 in profits -- for basically three days work.
Over three years, they made around $2.8M which worked out to about a 1819% return on their investment. Of course this is considered insider trading and they were eventually arrested. So the guys that were looking for credit card fraud were actually committing a different kind of fraud. There's gold to be mined in that data. See the complete story over at Bloomberg View.