why is The headquarters$-$based approach. This approach assumes that all assignees, regardless of location, are in one country $($i$.$e$.,$ a U$.$S$.$ company pays all assignees a U$.$S$.-$based salary, regardless of geography$).$ Cartus found that a small percentage of companies use headquarters$-$based approaches for long$-$term assignments $(4$ percent$)$ and short$-$term assignments $(5$ percent$)\mathrm{.}3$