If you are in possession of money, gold, silver, stocks or shares that amount to more than the value of 85 grams of gold or 595 grams of silver (at current market rates) then you are obliged to pay Zakah, i.e. 2.5% of total assets.
If you own this amount for a full lunar year (12 lunar months) then your Zakah is due at the last day of these 12 lunar months