To buy additional volumes of shares, you must: select an active investment, hit the "Buy more" button and select your desired number of shares.
Then click "Confirm transaction" to complete the process.
Your investment will then be increased by the specified number of shares.
Your investment opening price will then change accordingly. The investment opening price will change in order to ensure that it is equal to the weighted average price of the initial investment's opening price and the instrument price when the investment amount is increased:
NewPrice is the new price for opening the investment after increasing the investment amount.
Inv (0) is the initial investment amount.
Price(0) is the investment's initial opening price.
Inv is the amount of the increase.
Price is the instrument price when the investment amount is increased.