Explaining repo specialness

Abstract

We study the dynamics of specialness for 1-day repo contracts on Italian government bonds over a 10-year sample period. As predicted by Duffie's (1996) model, our results show that collateral supply is a significant factor for specialness. However, we enrich that finding by also showing a clear impact from repo liquidity, collateral riskiness, information uncertainty, and short-selling proxies, revealing the importance of speculative bond demand for specialness. During crisis periods, bond fire sales and European Central Bank interventions also have a large impact on repo specialness. We identify recurrent patterns for specialness around bond auctions. Specialness increases steadily from the auction announcement date until a few days before the auction settlement date, which is consistent with overbidding behaviour and a short selling of treasuries (via reverse repos) from primary dealers ahead of auctions.