Can digital repayment reminders reduce costly credit card delinquency? This paper analyzes data from a 2016 randomized controlled field trial of a reminder sent to 30-days-overdue credit card debtors via an app or online portal. The reminder significantly raised repayment rates, and amounts repaid, of high credit score delinquent debtors, but did not significantly raise the repayment rate of lower credit score delinquents. The reduction in average delinquency among treated debtors continues for at least 12 months after treatment and substantially reduces provisioning expenses of the credit provider. We find that 2.4 percentage points (CI 1.68–3.12) more treated than untreated debtors (64.3% compared with 61.9%) repay all arrears within the current repayment cycle. For the 84.4% of the sample who we observed logged in and saw the reminder, the effect rises to 2.7 percentage points (CI 1.95–3.50).

Since 2008, the WTI oil futures curve has been positively sloped for extended periods. We test whether changes in inventory alone can explain this atypically long contango. To do this, we estimate monthly VARs of the CME WTI oil futures spread and OECD and U.S. inventory in line with standard theory, and add petroleum consumption and implied volatility to the vector of endogenous variables. When we model the futures spread as one continuous series, results confirm two-way causation between inventory and the futures curve, as predicted by the theory of storage. However when we separate negative and positive futures spreads we find that: two-way causation between the futures spread and U.S. inventory breaks down; shocks to OECD petroleum consumption cause more negative spreads and shocks to U.S. consumption cause more positive spreads in addition to inventory-driven changes; and increases in volatility directly raise positive spreads. These new causal channels have become significant since 2008 and can be related to higher inventory, inelastic supply of oil and uncertainty about global economic conditions.