Plenty more events that just normal dividends and splits. Spinoffs, LT/ST capital gains returns, capital returns, liquidations, reorgs not to mention conditional events. None of these are particularly done well or consistently by Yahoo and Google. And both have their own issues with normal dividends and splits too.
How to adjust historical intraday data? (solved)
- Thread starter bellman
- Start date
They sometimes miss them altogether. But it's not THAT frequent. jharmon just doesn't like Yahoo Finance as he warns everyone on using their data. I don't need 30 years of perfect data as most of the errors happened very long ago or with stocks that don't make it into my liquidity category. Besides, paid data is known to have problems as well.
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bellman: Some examples: they put splits where there are none, they count some splits twice, put splits on the wrong date, missed some completely, they often are very late on performing corporate actions (there was a 310:1 split that was over two months late). At least on my trading signals there were about 50 mistakes in one year alone.
I have seen these types of errors not only in Yahoo, but also part of paid data services of many types. I have never used a corporate actions data source that isn't somewhat error-prone, which is somewhat crazy when you think about it. Why can't there just be a single, free database of all US corporate actions, with responsibility held by the individual public companies and/or DTCC to assure that the data is correct? It would make life so much easier for almost everyone.
I have heard that some specialized corporate actions feeds such as Markit are good, but I've heard it's expensive (how much I don't know), and the fact that they don't have a price list makes me imagine that it's very expensive. Anyone here have any experience with them or similar services?