  We examine the problem of dynamic reserving for risk in multiple currencies
under a general coherent risk measure. The reserver requires to hedge risk in a
time-consistent manner by trading in baskets of currencies. We show that
reserving portfolios in multiple currencies $\mathbf{V}$ are time-consistent
when (and only when) a generalisation of Delbaen's m-stability condition
\cite{D06}, termed optional $\V$-m-stability, holds. We prove a version of the
Fundamental Theorem of Asset Pricing in this context. We show that this problem
is equivalent to dynamic trading across baskets of currencies (rather than just
pairwise trades) in a market with proportional transaction costs and with a
frictionless final period.
