Abstract. Extending the approach of Jouini, Meddeb, and Touzi [Finance Stoch., 8 (2004) 1. Introduction. The concept of set-valued coherent measures of risk has been introduced recently by Jouini, Meddeb, and Touzi [16]. The basic question is how to evaluate the (financial) risk of a multivariate random outcome in terms of more than one reference instrument, for example if the regulator accepts deposits in more than one currency. This is of particular importance if transaction costs have to be paid for each transaction between assets including the reference instruments.This question became unexpectedly topical as the European Central Bank decreed [7] that temporarily, until the end of 2009, "the list of assets eligible as collateral in Eurosystem credit operations will be expanded" by "marketable debt instruments denominated in other currencies than the euro, namely the US dollar, the British pound and the Japanese yen, and issued in the euro area. These instruments will be subject to a uniform haircut add-on of 8%." See also [8].The following exposition is based on the model used in [16]; in particular, we assume the presence of proportional transaction costs modeled via a closed convex cone which goes back to [17]. A special feature of this model is that the risk of a d-dimensional random variable is evaluated in terms of m reference instruments with 1 ≤ m ≤ d. Usually m d will be true, but the case m = d is not excluded (and also, of course, neither m = 1, d > 1, nor m = d = 1).We shall make a few generalizations compared to [16]. First, we do not assume a "substitutability condition"; i.e., we do not assume that everything could be transferred into one distinguished currency. Second, we consider a general subspace M of R d as the collection