Asset purchase programmes, together with negative interest rates, may have exacerbated those differentials through signalling and non-linear effects, but their effect on exchange rates is, by and large, not fundamentally different from conventional policy. What is more, currency depreciation is a side-effect of policy and neither its main transmission channel, nor its objective.
That the NAMA timeline of purchases would turn into a drip-feed of bad news through the middle months of 2010 was clearly unfortunate.