  In this note we endow Kontsevich's category KMM of noncommutative mixed
motives with a non-degenerate weight structure in the sense of Bondarko. As an
application we obtain a convergent weight spectral sequence for every additive
invariant (e.g. algebraic K-theory, cyclic homology, topological Hochschild
homology, etc.), and a ring isomorphism between the Grothendieck ring of KMM
and the Grothendieck ring of the category of noncommutative Chow motives.
