By Dan Weil Financial stocks have dropped, with the S&P; 500 Financials Sector Index slumping 18% year to date. The year 2022 hasn’t been kind to financial-services stocks. The S&P 500 Financials Sector Index has slumped 18% year to date. But as of June 27 the drop left more than 70% of the North American financial stocks that Morningstar covers undervalued. The financial-research and -services firm’s analysts determine a fair value for each stock that they cover. “The median North American financial stock trades at a 21% discount to its fair value estimate compared with a 1% discount at the e…