Method 1: the earnings multiple
You take the normalised operating profit (EBITDA) and multiply it by a multiple for your sector. Most of the work is in the normalisation. You bring management fees to market level, take out one-off items and use a realistic yearly result (run rate). The multiple itself depends on size, growth, dependence on the owner and demand in the sector.
Method 2: discounted cashflow
You take the future free cash flow and discount it for time and risk. With a documented forecast, you get a higher result. If the business depends on the owner, the discount rate is higher and the result is lower. In the twelve months before a sale, you therefore also work on the valuation.
Method 3: the balance-sheet floor
The adjusted net asset value is the lowest price (the floor). For companies with many assets and for property holdings, the price is based mainly on this floor. For service firms, this method is less important, because most of their value is in the people.
Whatever the price, the sale is free of tax at company level if you hold the shares through a holding. See the Dutch holding structure for what that structure does and what it costs.
What raises or lowers the number
Buyers pay more for recurring revenue, a good spread of customers, processes that someone else can take over, and an administration in order. Two companies with the same profit and loss account can get very different prices because of these points. You can work on all of them in the year before the sale. See the preparation guide.