This is a highly absurd and exotic market. Prior to encountering this question, almost no one would seriously consider the possibility of a US President renaming a highly sensitive geopolitical Middle Eastern international waterway after himself.

If Trump were to announce this, it would be viewed as a massive provocation toward Iran, likely sparking fears of a blockade or military conflict in the Strait of Hormuz. This would immediately cause a spike in Crude Oil prices, negatively shock risk assets like the S&P 500, and drive capital into safe-haven assets like Gold.