Let
$V$ be a vector space and let
$T(V)$ denote the semigroup (under composition) of all linear transformations from
$V$ into
$V$. For a fixed subspace
$W$ of
$V$, let
$T(V,W)$ be the semigroup consisting of all linear transformations from
$V$ into
$W$. In 2008, Sullivan [‘Semigroups of linear transformations with restricted range’, Bull. Aust. Math. Soc.77(3) (2008), 441–453] proved that
$$\begin{eqnarray}\displaystyle Q=\{\unicode[STIX]{x1D6FC}\in T(V,W):V\unicode[STIX]{x1D6FC}\subseteq W\unicode[STIX]{x1D6FC}\} & & \displaystyle \nonumber\end{eqnarray}$$ is the largest regular subsemigroup of
$T(V,W)$ and characterized Green’s relations on
$T(V,W)$. In this paper, we determine all the maximal regular subsemigroups of
$Q$ when
$W$ is a finite-dimensional subspace of
$V$ over a finite field. Moreover, we compute the rank and idempotent rank of
$Q$ when
$W$ is an
$n$-dimensional subspace of an
$m$-dimensional vector space
$V$ over a finite field
$F$.