Why you should care about rising bond yields

Ignore bond yield creep at your own peril!

September historically is one of the worst months for the markets. In fact, September has, on average, seen slightly negative returns for the S&P 500 (^GSPC) dating back to 2006, per data from the Carson Group.

One day into September 2026, and we are being reminded that a slight negative return — or something far worse — could happen yet again. This time, it's happening at the hands of convulsing bond markets.

A worldwide government bond sell-off intensified today with a ferocity that should alarm every investor, big and small. The yield on the 10-year US Treasury note (^TNX) — the single most important interest rate in the world, the rate that sets the price of everything from a mortgage to a car loan to a credit card — just hit its highest level since January 2025.

Read more: How soaring Treasury yields could impact your finances

The 30-year yield (^TYX) is hovering around a two-decade high, which does nothing to help those planning for their long-term financial security.

And here is what makes this moment especially concerning: Bond yield creep is happening globally.

Japan's 10-year bond yield just climbed above 3% for the first time since 1996. British 10-year yields just hit their highest level since mid-2007. German 10-year bonds are at levels last seen in 2011 during the peak of the European debt crisis.

The major US stock averages all fell in response in early trading.

"The stock market has been able to ignore these moves so far this year. However, as we have seen in the past, higher yields don't matter for stocks … until they do," Miller Tabak strategist Matt Maley wrote in a note.

When the bond markets in the US, Japan, the UK, and Germany are all selling off at the same time, that is not a coincidence — that is a signal.

The signal is that investors worldwide are losing confidence in governments' ability to manage their debt, control inflation, and keep their fiscal houses in good order.

"Stocks have delivered positive returns across different rate regimes, with both rising and falling yields. The key distinction is what is driving rates," BCA Research analysts said. "When inflation is the market's focus, stocks and yields tend to be negatively correlated. When growth is the focus, that correlation is usually positive. Equities can thus absorb higher yields, but they struggle with rapid spikes. Conversely, while lower yields are mechanically supportive for multiples, a sharp decline often signals weaker earnings."

Let a volatile September commence!

Brian Sozzi is Yahoo Finance's Executive Editor, host of the Power Players with Brian Sozzi podcast, and a member of Yahoo Finance's editorial leadership team. Follow Sozzi on X @BrianSozzi, Instagram, and LinkedIn. Tips on stories? Email brian.sozzi@yahoofinance.com.

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