I wrote this in response to a question ealier this afternoon from Susan about SPY quotation data:

Susan,

Beware of SPY (or any equity that issues dividends and cap gains), including stocks. I think it is generally fine for intraday charts, however Stcokcharts is one of the few (I can't find another) that adjusts past prices not just for splits (they all do that) but also for dividends and cap gains distributions!

You can verify this by checking some major top or bottom in the past on another charting service and comparing to Stockcharts. They are different! Stockcharts historical data is artificially adjusted downward.

What does it mean? Stockcharts is fabulous for comparing long term total returns because it includes dividends. Good for buy and hold investors and value investors. However, for short term traders, you can't pinpoint old gaps, tops and bottoms that may come into play.

It is generally fine for intraday charts as they usually do the adjustments for dividends and cap gains once a quarter. Know when SPY is adjusted so this doesn't throw you a head scrathing curveball the day after.

I discussed this with the owner of Stockcharts, Chip Anderson, a couple months ago when he spoke at our monthly cycles meeting in Buena Park, CA and he confirmed what I just said. There is info about it on stoccharts if you snoop around.

Doug Milliken