 In the case of a special dividend, however, the company is signalling that this is a one-off payment.Therefore, special dividends do not markedly affect valuation or yield calculations, unless the amount is large -- in which case they "do" markedly affect valuation as they are a direct and large depletion of the assets of the company.Typically, special dividends are distributed if a company has exceptionally strong earnings that it wishes to distribute to shareholders, or if it is making changes to its financial structure, such as debt ratio.