Dive Brief: Days before The Wall Street Journal reported federal investigators were looking into American Express' sales to business owners, the company introduced more incentives for small businesses, including 30% off social media management tools from Sprout Social and four months of free access to BigCommerce for building an online store, the financial services company said Tuesday. In addition to offering resources for growing merchants' online presence, the company is also giving sellers up to 400,000 rewards points for business-related expenses such as office supplies, shipping and advertising. Business customers can now earn up to $250 cash back on select business purchases, too, per the company's Tuesday announcement.