As Pielke Jr. notes, the CRU hack itself didn't move the index much, but on the other hand the IPCC related mini-scandals did seem to have an effect. There also seems to have been a mild rebound as various reviews of CRU's behavior have come back giving the unit a more-or-less clean bill of health. This doesn't really fit Pielke's thesis, as the inquiries relate to Phil Jones and the UEA rather than the IPCC. And Pielke misses one possibly important date--March 29th (see the arrow right that I've added to the graphic), when Rajendra Pachauri, head of the IPCC climate change panel, was cleared of allegations that he was receiving payments from private companies.
Anyway, HSBC expects the CCI recovery to continue as the science reasserts itself. It will be interesting to see if public polls tracking belief in AGW and support for action against it show similar movement.