Bank of America Corp. sparked a stir in January—and a little envy—with just a few lines of disclosure in its fourth-quarter earnings report. The lender revealed it had slashed its 2020 corporate tax rate to 5.8% from what would have been 21%, thanks to finance work involving environmental, social and governance projects. That didn’t go unnoticed by Bank of America’s competitors. Executives at one large regional bank saw it, and talked to Bryen Alperin, director of renewable energy for tax specialist Foss & Company.