Abstract Reynolds stress is a key facet of turbulence self-organization. In the magnetized plasmas controlled fusion devices, zonal flows that are driven by averaged modify confinement performance. We address this problem with full- f gyrokinetic simulations ion temperature gradient-driven turbulence. From detailed analysis three-dimensional electric potential and transverse pressure fields, we show diamagnetic contribution to stress—stemming from finite Larmor radius effects—exceeds electrostatic factor about two. Both contributions in phase, indicating does not behave as passive scalar. addition, induced drift velocity found be mainly governed gradient phase modes rather than their magnitude. By decoupling drive intensity, property indicates careful dynamics crucial interpretation experiments simulations.