  Bessenrodt and Ono initially found the strict log-subadditivity of partition
function $p(n)$, that is, $p(a+b)< p(a)p(b)$ for $a,b>1$ and $a+b>9$. Many
other important statistics of partitions are proved to enjoy similar
properties. Lovejoy introduced the overpartition rank as an analog of Dyson's
rank for partitions from the $q$-series perspective. Let $\overline{N}(a,c,n)$
denote the number of overpartitions with rank congruent to $a$ modulo $c$.
Ciolan computed the asymptotic formula of $\overline{N}(a,c,n)$ and showed that
$\overline{N}(a, c, n) > \overline{N}(b, c, n)$ for $c\geq7$ and $n$ large
enough. In this paper, we derive an upper bound and a lower bound of
$\overline{N}(a,c,n)$ for each $c\geq3$ by using the asymptotics of Ciolan.
Consequently, we establish the strict log-subadditivity of
$\overline{N}(a,c,n)$ analogous to the partition function $p(n)$.
