Introducing salary bands in a growing company

We have grown from fifteen to sixty employees and salaries were negotiated individually over the years. Similar roles now differ by up to forty percent, and people talk. Leadership wants transparent salary bands without causing an exodus.

We benchmarked market data, defined levels for each job family and identified people below their band. Adjustments will happen over two review cycles. Communicating the change honestly seems critical. If you introduced salary bands, how did employees react, and what would you do differently?