CEOs will have to disclose how much they make relative to their workers under a new SEC rule that was mandated by the 2010 Dodd-Frank reform law and was approved today on a 3-2 vote, reports Sarah N. Lynch for Reuters. SEC’s CEO pay ratio rule The CEO pay ratio rule is being pushed by labor unions and other pro-labor organizations, but it would also be a good tool for investors to determine which companies are spending too much at the top. The US Chamber of Commerce, the Center on Executive Compensation, and other groups primarily made up of corporate…