Let $V$ be a paracompact strictly $K$-analytic space, $L$ a line bundle on $V$ and $({\mathfrak{V}},{\mathfrak{L}})$ a formal model of $(V,L)$. Let $({\mathfrak{V}}_{\rm red},{\mathfrak{L}}_{\rm red})$ the model of $(V_{\rm red},L_{\rm red})$ obtained by putting the reduced structure. Then ${\mathfrak{L}}$ is nef if and only if ${\mathfrak{L}}_{\rm red}$ is nef.