A securing element includes a head section and a shank. The cross-section of the shank changes in the axial direction in such a way that, by taking into account a qualitative and/or quantitative predetermined bending torque profile in the shank, the cross-section has a substantially uniform bending stress profile in the shank in relation to a securing element with a constant shank cross-section. An exhaust gas turbocharger having variable turbine geometry includes a VTG-guide vane configuration having at least one such securing element and being secured to a housing component of the exhaust gas turbocharger.