Finance or an Econ/Finance double major would be the way to go. Finance deals exactly with trading and valuation; Econ would give you a broader perspective on why and how the overall markets change.
If I had to pick just one I would go with Finance. Interpreting financial statements and understanding business ratios will help with assessing a business' financial health which leads to more informed business analysis. Economics, on the other hand would help more with external forces like competitive environment, money supply, interest rates, etc., and there impact on a company.
Economics or Finance?
