If a minor owns shares that do very well – (they may be sold because they are taken over at an extreme price, or they are just too high a price not to sell) then the resultant net taxable capital gain will be taxed at penalty rates (as high as 66%) where the child is still under 18.Also, if dividends paid on the shares (together with other investment income; eg interest) total more than $416 in a year, the child is also taxed at penalty rates (as above).However, if the shares were held in a trust, then the same capital gain and investment income may well be able to be distributed to another family member over 18 with substantially less tax.