Morningstar vs. Yahoo/Google Finance

So I used to use Bloomberg terminal, and now that I am at a smaller company, I switched over to Morningstar. I noticed that the data between Morningstar vs. Yahoo/Google Finance could be dramatically different. If anyone knows why, any explanation would be greatly appreciated.

Example: Fund SLCGX vs. S&P 500 TR

Based on morningstar and 10 year data, SLCGX outperforms by a considerable amount (8/27/2005 to 8/26/2015). However, when looking at yahoo finance, S&P TR actually outperforms.{“showArea”:false,“customRangeStart”:1125126000,“customRangeEnd”:1440572400,“lineWidth”:“4”,“lineType”:“line”,“range”:“custom”,“showPrePost”:false,“didDisablePrePost”:true,“allowChartStacking”:true}

I suspect morningstar is correct, but I cannot figure out why the difference is so dramatic (is one of the charts using S&P price index instead of total return? is one of the charts taking into account of certain fees, such as front load fees?)

Thanks for your input!

Use Morningstar.

Yahoo is tracking NAV for SLCGX. So a dividend or capital gains payment will drop the NAV and Yahoo accounts for that as negative performance. You can see that if you look at the blue diamonds at the bottom.

I like to use the performance tab on Morningstar to look at numbers like this.