The one thing in markets everyone should be watching

• The 10-Year US Treasury yield is arguably the most important thing to watch right now for investors.
• The 10-Year yield has soared to levels not seen since 2007, and that's having a big impact on stock prices.
• Here's what you need to know about what bond yields are doing to markets and the economy. 

Surging bond yields have left their mark on the stock market in recent weeks, and the 10-Year US Treasury yield has become arguably the most important thing for investors to watch.