Central bank purchases and debt management shape Bund repo specialness
A new European Central Bank working paper analyzes how debt management office interventions and Eurosystem asset purchases jointly affected German government bond repo specialness between 2015 and 2024. The study finds that while central bank purchases depress repo rates, debt management repo lending effectively mitigates collateral scarcity.
Four times the impact on repo rates
A new ECB working paper quantifies the security-specific effects of public-sector interventions on German government bond repo specialness from 2015 to 2024.
The authors find that Eurosystem asset purchases depress repo rates about four times more than purchases by the German Debt Management Office (Deutsche Finanzagentur, DFA), with a 1 percent free-float purchase lowering repo rates by 0.4 basis points compared to 0.1 basis points.
Conversely, DFA repo lending operations raise repo rates by roughly 0.2 basis points per 1 percent of outstanding volume, proving twice as effective as outright secondary-market sales.
The study demonstrates that the DFA actively responds to Eurosystem purchases by expanding repo lending within days to supply scarce collateral.
When ample supply meets surging demand
Despite historically large increases in public-sector collateral supply, repo specialness reached extreme levels during the 2022-23 episode, with some Bunds trading up to 60 basis points below the deposit facility rate.
The paper reveals that surging demand from hedge funds using bonds for hedging and arbitrage overwhelmed public backstops.
Because the euro area repo market is segmented and public facilities transact at market-clearing rates rather than providing price insurance, collateral supplied did not fully eliminate scarcity premia.
Limits of public backstops
This rigorous study exposes the structural limits of central bank collateral management.
Debt management interventions offer vital quantity insurance against scarcity.
However, they remain powerless against aggressive hedge fund positioning in segmented markets.