In this paper, the issue of how transmission power losses should be allocat
ed is addressed. First, it is shown that existing methodologies allocate in
teraction components regardless of the size of the involved partners. Then,
several alternatives to split those terms are suggested which somehow take
into account the relative contribution of each transaction. Although the i
deas are presented by resorting to unbundled branch power flows, the propos
ed schemes are applicable on a nodal basis. A real example is finally inclu
ded shelving that the total losses assigned to a transaction may differ sig
nificantly depending on the allocation methodology adopted.