  An inverted mass hierarchy in the squark sector, as in so-called "natural
supersymmetry", requires non-universal boundary conditions at the mediation
scale of supersymmetry breaking. We propose a formalism to define such boundary
conditions in a basis-independent manner and apply it to generic scenarios
where the third-generation squarks are light, while the first two generation
squarks are heavy and near-degenerate. We show that not only is our formalism
particularly well-suited to study such hierarchical squark mass patterns, but
in addition the resulting soft terms at the TeV scale are manifestly compatible
with the principle of minimal flavour violation, and thus automatically obey
constraints from flavour physics.
