Answer
If the company is a trading investment then Zakaat is payable on the capital amount as well as the dividends. If the company is not a trading investment and only receives income, for example, from rentals of properties, then Zakaat is liable only on the dividends.
In this case, as a shareholder of a trading investment, Zakaat is due at 2.5% of the 40% shareholding on the capital, as well as on the dividends.
and Allah Ta’ala Knows Best
Mufti Ebrahim Desai