\Pr\left( \left\| \frac{1}{t} \sum_{i=1}^t M_i \right\|_2 > \varepsilon \right) \leq d \exp \left( -C \frac{\varepsilon^2 t}{\gamma^2} \right).
where \lVert M \rVert_2 \leq \gamma holds almost surely and C > 0 is an absolute constant.