  We present a method which relies on loop contributions from four-top SMEFT
operators to single Higgs observables to contrain their Wilson coefficients.
Such loop-induced terms have a non-trivial interplay with the extraction of the
trilinear Higgs coupling. We show that this strategy can, for some operators,
lead to more stringent bounds than direct measurement via top quark data.
Finally, we mention some recent developements in the treatment of $\gamma_5$ in
dimensional regularisation in the context of the SMEFT.
