To address the difficulties presented by the very nature of the risk, the designers of operational-risk measurement frameworks have had to be more innovative, take bigger steps into new territory, and be more willing to step away from traditional - and comfortably familiar - techniques than their counterparts in the market- and credit-risk arenas.
We have had negative rates for some years now and so far their implications have been far less exciting or radical than some might have thought before entering the negative territory. Basically, negative interest rates have just been a continuation of low interest rates.