This commenter comes into every single thread about trading and talks about buying data from ebay, then consistently demonstrates that he doesn't know the first thing about due diligence on financial data. Each time I try to ask him about his data quality or methodology at even a high level, he responds by accusing me of wanting to steal his work or stop the democratization of data.
I'm going to reiterate this right now: you are not going to find data valuable enough for trading insights on ebay. Go look at the prices of historical data for various time resolutions at TickData or CBOE Livevol and then ask yourself if cheap, competitive data on ebay is too good to be true.
If the data is competitive, it's expensive. If it's not competitive, you shouldn't be paying for it, especially not from ebay. The first time I read about him doing this I was puzzled, now I'm getting increasingly frustrated because it's blatantly false information.
Unless you are day trading you don't need such a granular data format, so please stop saying you need to spend thousands and thousands of dollars to be able to back test a trading strategy
If your data doesn't need to operate on an intraday scale, you can get perfectly accurate real time or historical data for free just by using a reputable broker like Interactive Brokers. At that point there's no need to buy the data on ebay, so I still don't understand why you ever would.
Actually I have checked IB API and it is very restrictive, e.g. you cannot request let say all daily data for all symbols for 2007 for example or even for one day for that matter...
I'll third this comment. Some more details on what you trade, where you trade, how long you've been doing it, performance metrics, etc... would be fascinating.
As you can see I am paranoid, because the more people trading the same strategy, the less effective it becomes, not to mention, if someone knows your trading strategy it can trade against you... it’s a zero sum game after all...
All that said, here are the 2 most important advises I wish someone told me when I started years ago:
Have an iron clad risk management strategy for your portfolio, e.g. if you are willing to risk 1% of your capital on any given day and tomorrow happens to be the Black Monday and all stock go down 50% you still have to be sure you’ll loose only 1% if you have to sell everything...
This is where the back data comes into play – the goal is to back test not how much money you are going to make, but how much money you are going to loose in the worst case scenario if you have to liquidate everything and move to all cash.
If you have this working 100%, you just need a trading strategy with a minimal edge and you’ll make money in the long run in the market and the compounding effect will really make you a rich person (rich person to me is someone who makes more money then he spends, WITHOUT working more than 1 hour a day)
And the second advice is never ever trust and buy a trading strategy from someone, the fact he is selling or "teaching" a trading strategy means it is not working and he is trying to make some money by scamming people and selling the dream, all those trading educators cannot make money trading and that’s why they are coming with up with those fake trading courses... just check this website to see the magnitude of this scam and how people are loosing their life savings...
I just don’t know why FBI, SEC and the government is not doing something to stop those guys...
