Bond yields are at the heart of almost all asset prices in the market, and by understanding how they function and the reasons for their changes, investors can come to an understanding of what is going on in the stock market, currencies, and within their own portfolios.
Step 1: What makes a bond move markets?
A bond is a loan. The bondholder lends money to a government or corporation, which pays regular interest, known as the coupon, and returns the principal at maturity. A 10-year Treasury bond means lending to the U.S. government for a decade.
After they have been issued, most bonds trade in the secondary market, mostly over the counter between broker-dealers. Two figures determine a bond's value in the market: its price and its yield. The yield is the annual return an investor can expect if the bond is held to maturity, and it is closely linked to the price; the two move in opposite directions. When current interest rates fall, older bonds with higher fixed coupons become more valuable and trade at a premium. Alternately when rates rise, those same coupons look less attractive, and the bonds trade at a discount.
Step 2: Why the 10-year Treasury is the anchor
The 10-year Treasury yield functions as the market's risk-free reference point, and most other assets are priced in relation to it. When the yield rises, mortgages, corporate loans, and government borrowing all become more costly. Equity valuations usually shrink because future earnings are discounted at a higher rate. Since a rising risk-free option makes all other assets appear relatively less attractive, a risk-off sentiment can spread unless expected returns from other investments increase to make up for it.
This is the reason why traders watch Treasury auctions and Federal Reserve guidance so closely, as these are the means through which capital is transferred between markets.
US10Y, US500, Source: Tradingeconomics.comStep 3: How rising yields affect stocks and currencies
The value of growth stocks, especially those in the technology sector with high valuation, comes largely from the earnings that are expected many years into the future. The further into the future these cash flows lie, the more they are discounted when interest rates rise, meaning that growth stocks generally suffer more than value sectors such as utilities, consumer staples or financials since the latter have earnings that are concentrated in the near term or directly benefit from higher interest rates.
In the currency markets, higher relative yields tend to draw foreign capital and strengthen a currency, so a rally in U.S. yields often coincides with dollar strength. However, the situation is not always the same. If yields rise on fears about debt sustainability rather than due to a more contractionary Fed policy, the dollar may weaken instead, as foreign holders pull back exposure. It is just as important to understand why yields are moving as much as the move itself.
Step 4:Reading the equity risk premium
The equity risk premium (ERP) offers a simple gut check on whether stock market risk is being adequately compensated relative to Treasuries:
ERP = S&P 500 earnings yield − 10-year Treasury yield
The S&P 500's earnings yield is the inverse of its P/E ratio. As of mid-2026, a forward P/E near 20.5 implies an earnings yield of roughly 4.9%. With the 10-year Treasury near 4.8% in early September, the ERP sits at only about 0.1 percentage points, thin by historical standards, where the long-run average has run several points higher.
When the ERP compresses this close to zero, stocks are priced with little margin for error: earnings need to keep growing briskly, or yields need to decline, to justify current valuations. While it doesn't predict a selloff on any given date, it offers a measurable answer to a question that instinct alone can't answer and that is: how well is equity risk actually being paid for right now?
Step 5: What to watch
Treasury auction results (bid-to-cover ratio, indirect bidder share): weak demand often precedes yield spikes.
Fed guidance and the dot plot: helps distinguish policy-driven yield moves from fiscal-driven ones.
The ERP trend, not just its level: a falling ERP alongside rising yields sends a different signal than a falling ERP alongside stable yields.
Sector rotation: growth-to-value flows often confirm that markets are taking a yield move seriously.
