Unless your share trading as a business, it would be...

Unless your share trading as a business, it would be 30%....company tax would be 27.5% but for the FY2020-21 it will be 26%

If you make a loss from trading for the FY, you can deduct it from your Income Tax. Eg. If you had a Taxable Income Tax for the year $70,000 and you made a $20,000 loss from share trading, you can minus the $20k from the Income Tax ($70-20k) = $50,000. Therefore you will only get taxed on $50,000 instead.