This bill, known as the "Close the Round-Tripping Loophole Act," significantly modifies the calculation of Global Intangible Low-Taxed Income (GILTI) under the Internal Revenue Code. It introduces a "round-tripping ratio" to reduce the net deemed intangible income return for United States shareholders. This ratio is applied to a shareholder's net CFC tested income, effectively excluding certain income from the GILTI calculation. The legislation defines round-tripped net CFC tested income as income derived from property sold to U.S. persons or property not established for foreign use, as well as income from services not established as provided outside the U.S. Furthermore, the bill limits the deduction for GILTI by the amount of this round-tripped income, reducing the 50 percent deduction proportionally. An exception ensures that small taxpayers , with average annual gross receipts not exceeding $100,000,000, are not subject to this round-tripping ratio. These amendments are designed to apply to taxable years of foreign corporations beginning after the date of enactment, aiming to prevent companies from avoiding U.S. taxes through income repatriation schemes.