In their paper, “Foreign Holdings of U.S. Treasuries and U.S. Treasury Yields,” Daniel O. Beltran, Maxwell Kretchmer, Jaime Marquez, and Charles P. Thomas explore the possible outcomes, finding that such a move on the part of foreign holders would indeed make a significant impact. Note the authors:
By our estimates, if foreign official inflows into U.S. Treasuries were to decrease in a given month by $100 billion, 5-year Treasury rates would rise by about 40-60 basis points in the short run. But once we allow foreign private investors to react to the yield change induced by the shock to foreign official inflows, the long-run effect is about 20 basis points.
The full paper is published in The Journal of International Money and Finance.