It looks like your post title is cut off, so I can only answer generally: the risks of not using something depend on what “US” means in your context. If you mean “not using the U.S.” in an investing sense, one common risk is missing exposure to the U.S. market while also taking on currency risk from non-U.S. assets, since exchange-rate changes can affect returns.

Possible meanings

  • If you mean not using U.S. investments , the main risks are lower diversification, different return patterns, and currency fluctuations affecting your gains or losses.
  • If you mean not traveling to the U.S. , then the “risk” is usually opportunity cost, not safety risk, and it depends on your reason for going.
  • If you mean not using U.S.-based services, products, or systems , the risks could include reduced access, compatibility issues, or higher costs.

Investment angle

For non-U.S. investors, currency movements can either help or hurt returns, because your home currency and the asset currency both matter. The source also notes that hedging can reduce currency risk, but it may add cost, and the right choice depends on whether you are investing in stocks or bonds.

What I need

Your headline is too incomplete to answer precisely. A clearer version would be: “What are the risks of not using U.S. stocks?” or “What are the risks of not using the U.S. for travel?”