  We revisit non-marginal half-BPS solutions of M-theory in the framework of
the possible existence of an underlying E11 Kac-Moody symmetry. In this
context, non-marginal BPS solutions of M-theory can be described as exact
solutions of the brane sigma-model E10/K(E10), extending results obtained
earlier for marginal BPS solutions. We uncover an elegant and simple algebraic
structure underlying the bound states by looking at subalgebras embedded in
E10. Furthermore, we show that the non-marginal BPS solutions can be obtained
from the elementary marginal ones by the action of K(E10) transformations.
