All Large Taxpayer Units (LTUs) and Regional Tax Offices (RTOs) would remain open on Saturday (August 20). In this regard, the Federal Board of Revenue (FBR) has issued instructions to all Chief Commissioners of LTUs and RTOs here on Friday. According to the FBR, all the field offices shall remain open and observe normal working hours on Saturday. The concerned Chief Commissioners should ensure the attendance, FBR added.