Salary ceiling - teto salarial.
A salary ceiling could be a figure: "The CEO´s salary ceiling is 678,000 R$ in this company. The executives immediatelly under him (CFO, CTO and CIO) have the salary ceiling of 406,800 R$.
Or it may be expressed as multiples of a given salary (at least in Brazil):
The CEO´s salary is up to a ceiling of 1,000 minimum wages, whereas the salary ceiling of the others executives is of 600 minimum wages.