What you're saying here is that an institutional investor wants to buy MSFT at a price that does not reflect their new demand for 100,000 shares. That order, absent some external force that will put downward pressure on the shares (which, if so, why buy now?) will naturally raise the price of MSFT for everyone in the market.
The investor, in other words, wants something for nothing: they want to trade at a price that doesn't reflect their demand, and for some other market participant to take the hit for selling below the true demand.
Should the price increase to 4.00 as soon as he stops in front of the pump to 'reflect the new demand'?
In my example the Gas Station is doing a bait-and-switch where the price was 3.99 until you pull out your credit card. HF Traders are not doing a bait-and-switch since they are separate entities than the original seller but they are making money off the same principal as a bait and switch.
In the vast majority of instances the HFT are not buying something and reselling it at an inflated price before another interested party has access to it. They are changing the price on things they themselves had already set the price for.
A closer analogy than what either of our gas stations makes is I own ten gas stations in a line down the high way. At the first one a tanker truck pulls up and takes all the gas I have at that gas station, then at another and another and another so on down the line such that I no longer have any gas.
When I go to replenish my stocks I find out that some big company needs tons of gas and has driven the price well above the 3.99 I was selling for. This means I just took an extreme beating in the selling gas industry. I don't mind, that is a cost of doing business.
Then the next week they come and do the same thing and on and on for years. Eventually, I tell the manager of the first gas station to call all the other managers the minute a tanker truck shows up so we can adjust our prices and not get wiped out.
The big gas company now has to pay a much more appropriate rate for the gas. This drives them crazy so they go on 60 minutes and tell everyone on the planet that the game is rigged because I have this super sophisticated technology that lets me "front run" them.
You hear this and start thinking to yourself, man I can't trust that they are going to charge me more money for this gas as soon as I pull into the station. You start buying less gas and calling your senator. The big gas company then goes on CNBC and says, "See I told you those little gas companies were no good. Now they are eroding the faith of gas buyers in the fairness of the market place."
When in reality all that is happening is that the big gas company can no longer take advantage of me to get cheap gas.
Wall St. has a long history of fraud and skimmers so it is understandable to say the HTF isn't that bad relative to other things.
But we should be trying to make the markets more fair and give people more confidence that everyone isn't getting ripped off.
I still take issue with your idea that the HFT is injecting itself into some preordained transaction. Information that there is a lot of demand for something should raise the price for that thing.
Large institutional buyers already have huge information/infrastructure advantages. Why should they also be given assn exemption from market dynamics that no one else received?