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white_devil

It sounds like you work for the financial industry too.

> The HFT trader

You say it like it's a person making trades.

> I've benefited because I can buy/sell at a price close to the quoted exchange price, which didn't use to be the case.

What's a "quoted exchange price" if it's not the price you actually pay?

> Short term investing is "bad" because you're not investing in the future success of the company you're trading on the basis of what you think the market is going to do.

Isn't this what HFT is all about?

Trading on insider information is bad, of course. But if you're on a level playing field, I don't see anything wrong with profiting from something you correctly predicted short-term.

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> What's a "quoted exchange price" if it's not the price you actually pay?

The actual price you have to pay is based on how much you want to buy and how much other people are willing to sell at what price.

People who want to buy give a "bid" price and people who want to sell give an "ask" price. Whenever there is an ask price that is lower than a bid price, a sale takes place. This results in the lowest ask price always being higher than the highest bid price. The quoted exchange price will be somewhere in between the two prices.

If you want to sell right away, the most you can get is the highest bid price on the books. If you want to buy right away, the cheapest you can get it is the lowest bid price on the books. This means that you have to pay more than the quoted exchange price to buy and receive less than the quoted exchange price to sell.

I do - but a 'proper' long term investor that cares about the price in 20 years time.

The quoted exchange price is an average of the buy/sell offers available, there is no guarantee if you try and trade that you will pay that amount. Especially if you are shifting large blocks of stock.

There is nothing wrong with "short term predicting" but it isn't investing. It is often a very easy way to lose money, "bad" doesn't just mean morally so. It comes down to time horizons, how much you want to make, and how many people are also trying to predict that event. You can correctly predict that event and still not make money as it is already priced in.

> What's a "quoted exchange price" if it's not the price you actually pay?

The mean of the bid and the ask, generally. For a daily close price it can be a fifteen-or-so minute average thereof.

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