Which Web Site Has The Best Stock Market Data?

I've done research on stocks for years. I would mainly use Morningstar, and Yahoo Finance. I trusted their data was accurate. Though recently I started really digging into financials and comparing them to other financial websites. I noticed something alarming. One financial web site would display different data than another!! Why is this? How am I supposed to make accurate financial calls if the data is different on each website?

Perhaps this statement rings true:

A man with a watch knows what time it is. A man with two watches is never sure. Segal's law

For example, take VMware Inc. (VMW) in which I did a long put option in my previous post. Each web site for VMW had a different forward P/E:

• Yahoo Finance – 49.56
• MSN – 74.11
• AOL's DailyFinance – 51.36
• Morningstar – VMW, 49.3
• CNBC – 54.0
• Google Finance – N/A

Which one is correct? One was much higher than the others (MSN), and why the difference? I understand some may have a real-time calculation of the number, while others may do a daily or weekly calculation. UPDATE: I checked later and most had a different forward P/E so some calculate it in real-time. Granted from any of the web sites, you know the stock is way overvalued, but this might not be the case if the stock was in the 20-30 range. The range in the above sample is over 24 points!  In theory, that could make the stock appear cheap on one web site, while expensive on another.

OK, maybe I'm being a little harsh.  Forward P/E with specifically the E (earnings) can be estimated by using what the company expects, or what the consensus of the stock analysts expect. So let's use a simple number that's reported to the SEC, annual revenue for 2010. From the same web sites here is what I found:

• Yahoo Finance – 2.63 Billion
• MSN – 2.63 Billion
• AOL's DailyFinance – N/A (2010 was not available)
• Morningstar – 2.63 Billion
• CNBC – N/A (2010 was not available)
• Google Finance – 2.63 (had to manually add up the quarters)

It's great that the ones that displayed 2010 data had the correct number, but 2 out of the 6 did not have the 2010 data yet. I'll also grant you that VMware, is no Apple (AAPL) so, it's not a highly watched as other stocks, but overall this is concerning. For me, I primarily still use Yahoo Finance and Morningstar for my financial research. I've always assumed their data was accurate.  Based upon this simple sampling, and other stocks I've researched in the past, it appears so.  I've tried to use Google Finance, but find their real-time data is often delayed and lacks some of the financial data I need for my research.

Ideally using the SEC website is where you'll get the most accurate information, but it takes much more time to digest the data. I would prefer not having to always go to a company's 10-Q or 10-K statements.

When investing in stocks, Be aware that the ratios listed on the popular financial web sites might not be accurate or have the latest data.  I find it ironic that 15 years ago, this information was not available publicly. You either got this information from your stockbroker or had to subscribe to an expensive stock research company. Though it's now available for free, it doesn't help if conflicting data is available online.

Readers: What website do you use to do your financial research and why?