Under the current system, you, your wife and adult child could each take $33000 in dividends, and you'd collectively pay much less tax than you taking $100,000.  The investment portion is just  one of fairness.  Those who do not own corporations need to pay tax on investment income (the interest on the 50,000, not the principal) and there might be better vehicles to use to invest that money, such as RRSPs and TFSAs, or look into the IPP or insurance option, which G &M helpfully explained.