Royal Dutch Shell RDS.B -0.04% PLC and Barclays BCS 0.09% Bank PLC said they would take large charges attributable to the U.S. tax overhaul —joining a parade of global firms in recent days disclosing how American tax-bill changes will affect their bottom line. Shell estimated its U.S. tax-related charge in the fourth quarter could amount to between $2 billion and $2.5 billion, stemming from a reduction in the value of its deferred tax assets. Companies can log such assets during unprofitable periods and can use them to offset future tax payments. Those assets—essentially credits toward future tax payments in the U.S.—are worth less on paper after the tax overhaul sharply reduced headline corporate tax from 35% to 21%. Barclays, meanwhile, said it would take a noncash charge of £1 billion ($1.3 billion) in […]