dafong, are you perhaps fairly new at this game? I have surmised that from your initial question. The only analyst reports to be trusted, and then only with caution, are those coming from independent agencies that don't have direct ties to Wall Street.
Let me just say that in general you should disregard any buy or hold (which in analyst speak means sell) recommendations coming from most analysts. Sell recommendations are extremely rare.
The reason you can not trust most analyst reports is that they are often slanted to serve the interest of the financial institution they work for. Thus when GS wants to dump a large position they are having trouble getting rid of, a buy recommendation is generated. When GS is courting a new client, a very complimentary analyst report appears, etc. When earnings from a company whose stock is in their inventory are going to be weaker than expected, a revised lower estimate of earnings is released. Then when the lackluster earnings are reported, they are said to "have beaten analysts" estimates, when in reality they sucked. When the dollar is sinking like a rock and most of US company XYZ's gain in dollars is coming from overseas sales and is almost all due to the exchange rate rather than organic growth, the analysts issue a glowing report touting the strong quarter XYZ had.
In a word beware of anything coming from the pen of a so=called Wall Street "Analyst". They are paid to tell white lies, and they know it.
If you are trading intraday you don't care about fundamentals, and you can just ignore analysts altogether. If you are investing, either rely on independent analysis, or better yet, do your own using company and SEC reports..
You can use obviously self-serving and silly analyst, up and downgrades to make money by fading them. But always check them out first because every now and then an analyst will issue an objective report just to keep you guessing.
