I'm not privy to who is making the trades - but if I have one...

I'm not privy to who is making the trades - but if I have one million shares in one hand and one million shares in the other it appears as though I can buy and sell the shares between each of my hands and manipulate the share price in any which way I choose. As a peasant I am restricted to a minimum of 500 shares per trade and I'm unable to buy or sell in a way which can manipulate the market (ie one or two points either way). It appears as though whomever is buying and selling these shares are not bound by the same rules. Just now a single trade of 27 shares was able to drop the market by 12c or 4.5%. It astounds me that these practices go on unchecked.