It’s not the pirates, apparently. Rumours that the Sirius Star was in some way connected to Glencore seem unfounded. And even if there was a connection, could it explain Glencore’s current CDS spread?
Something’s up. Here’s where the 5 year senior CDS are trading today:

Glencore’s results revealed no secrets last week either: by all accounts they were rather rosy.
So it’s over to you, Mayfair…
