If the principal component and financial intermediation services amount with respect to the interest component of a lease have been taxed pursuant to this section, then the gross lease or rental payments shall not be subject to additional tax. 805. Basic interest rate For purposes of this chapter, the basic interest rate with respect to a debt instrument, investment, financing lease, or account shall be the applicable interest rate (as determined in section 511). For debt instruments, investments, or accounts of contractually fixed interest, the applicable interest rate of the month of issuance shall apply. For debt instruments, investments, or accounts of variable interest rates and which have no reference interest rate, the applicable interest shall be the Federal short-term interest rate for each month. For debt instruments, investments, or accounts of variable interest rates and which have a reference interest rate, the applicable interest shall be the applicable interest rate for the reference interest rate for each month. 806. Foreign financial intermediation services (a) Special Rules Relating to International Financial Intermediation Services Financial intermediation services shall be deemed as used or consumed within the United States if the person (or any related party as defined in section 205(e)) purchasing the services is a resident of the United States. (b) Designation of Tax Representative Any person that provides financial intermediation services to United States residents must, as a condition of lawfully providing such services, designate, in a form prescribed by the Secretary, a tax representative for purposes of this subtitle. The tax representative shall be responsible for ensuring that the taxes imposed by this subtitle are collected and remitted and shall be jointly and severally liable for collecting and remitting these taxes. The Secretary may require reasonable bond of the tax representative. The Secretary or a sales tax administering authority may bring an action seeking a temporary