Before revision:  We show that the no-arbitrage of second kind property (NA2 in short), introduced by \mbox{%DIFAUXCMD ras09 markets, allows  to provide a closure property for the set of attainable claims in a very natural way, under a suitable efficient friction condition.
After revision:  We show that the no-arbitrage of second kind property (NA2 in short), introduced by \mbox{%DIFAUXCMD ras09 markets, allows us to provide a closure property for the set of attainable claims in a very natural way, under a suitable efficient friction condition.