UMR isn't the only margin related event this year. Jo Burnham at Opengamma sets out what may happen this year.

OTC people are focussed on UMR, but there may be other margin impacts to be planned for. Jo Burnham at OpenGamma explains why both cleared and uncleared products may have big changes coming this year.  One major change may be much wider adoption of VaR models replacing SPAN. Jo explains it all over on her blog post here.