(The opinions expressed here are those of the author, a columnist for Reuters)ORLANDO, Florida - If the "Sell America" trade heats up, who is most likely to stoke the flames? They're also ⁠the ‌biggest investors in America Inc, amid the frenzy to take part in the U.S. tech and artificial intelligence equity bonanza. So who would be most likely to reduce these purchases moving forward, or even bring some of that money home? But Japanese investors' home bias is very strong, and their share of U.S. assets relative to their total holdings is modest. SMALL COUNTRIES, BIG EXPOSUREUltimately, it's smaller countries or "middle powers" that appear most likely to rebalance away from American assets, based on the size of their U.S. securities holdings relative to their overall assets.