Without complete information about the employee, such as their designation, number of years of experience, and qualifications, it would not be fair on our part to comment on the given salary. Additionally, I'm sure they must have joined on a higher salary than in the past in your company. You can look at the total percentage and convince them.
Salary Structure and Market Alignment
When the salary structure is finalized, there is a general tendency to align the figures with the market to ensure you do not lose your best talents to competitors. Otherwise, a 10% hike is good enough after the probation period, and as Abedeen mentioned, measuring ROI is very important.