I assume you are not classing yourself as a share trader but as a share investor.
If you buy blue chip shares and received $1000 dividends in a year but pay $2500 in interest on a loan to buy the shares you are in a negative geared situation where you have a $1500 loss against dividend income which can be used to reduce other taxable income (salary and wages)
If no dividends are received but the interest paid is still $2500 but there is a genuine intention to receive dividends then the whole $2500 can be used to reduce other income.