Consider two days on which a technology ETF rises by the same amount. On the first, long-dated Treasury yields are falling. On the second, they are rising. The price change is identical; the market is saying two different things.
Why rates reach into equities
The value of any asset that pays out far in the future is sensitive to the rate used to discount those payments. Long-dated bonds are the plainest example — this sensitivity is what duration measures — but growth-oriented equities share the trait, because much of their expected earnings lies years ahead.
So when long yields fall, long-duration bonds and growth equities tend to be helped by the same force. When an equity move comes with that tailwind, it is at least partly a rates story. When it comes against rising yields, something else is driving it.
Description before prediction
None of this tells you what happens next. The relationship between equities and rates is not fixed; it has changed sign over the years, and it can change within a single regime.
What a cross-asset reading gives you is a better description of the present: “technology ETF momentum is strengthening while long-duration Treasury yields are declining” carries more information than “buy QQQ”, and it leaves the decision where it belongs.
This note is educational. It is not investment advice.