The tax raise can be dealt with in several ways or a combination of all:
1) decrease outgoings (cost of raw materials, cost of staff)
2) decrease outgoings (dividends to shareholders)
3) increase incomings (raise prices).
Where there is a monopoly (or similar types of market failure such as oligopoly) most of the tax raise will be dealt with by 3).
If there is a competitive market then the tax raise will fall somewhat on 1) and 2) as well.
This is one reason that breaking up monopolies is so important.