Regressing Stock Price changes

Hey!

I am a financial analyst, but not very good at econometrics. I need to to find out how interest rates in USA affect the stock prices.

Now I am trying to figure out other independent variables, like GDP, earning reports etc. But the problem is that GDP is also correlating with earnings reports etc.

So what explanatory variables would you suggest me to use?

Thank you very much,

Kaspars

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