My client received an amended 1099 from a brokerage firm for 2020. His 2020 return has already been e-filed and accepted. The amended form changed a cost basis by $2 which in turn caused ST capital gains to increase by $2. When I change the amounts on the 1040X to include the additional $2 gain, the tax does not change. My question is, do you have to file the amended return if there was no change of tax? Will the IRS be looking for an amended return?

Any input would be appreciated.