Walmart, the world’s largest retailer, expects an extra $2 billion this year from a GOP-led tax overhaul, money that it will invest in pay raises for employees and upgrades to an online business whose growth slipped at the end of last year.

Not only will the Bentonville, Ark.-based company’s effective tax rate be 26 percent or lower, compared with a previous projection of 32.5 percent, it will also get a boost from changes to rules governing depreciation of buildings and equipment, Chief Financial Officer Brett Biggs said Tuesday.