We study central bank interventions in times of severe distress (mid-2010), using a unique bond-level dataset of ECB purchases of Greek sovereign debt. ECB bond buying had a large impact on the price of short and medium maturity bonds, resulting in a remarkable “twist” of the Greek yield curve. However, the effects were limited to those sovereign bonds actually bought. We find little evidence for positive effects on market quality, or spill-overs to close substitute bonds, CDS markets, or corporate bonds. Hence, our findings attest to the power of central bank intervention in times of crisis, but also suggest that in highly distressed situations, this power may not extend beyond those assets actually purchased.