Why Stock Prices Move
The plain answer
Section titled “The plain answer”A stock price moves when the next trade happens at a different price from the last one. That happens when buyers will pay more, or will only buy for less, than they would a moment ago.
The business can be unchanged that day. The price still moves because the future is being repriced.
How it actually works
Section titled “How it actually works”Investors discount expected cash flows. If expected profits rise, or if people accept more risk, prices tend to rise. If rates on safer assets rise, risky assets often look less attractive and prices can fall.
News is one input. Liquidity is another. A large seller can move a thin stock without a new fact about the company. Index funds buying or selling when they rebalance can move prices too.
Short-term moves are noisy. Long-term prices still have to connect, loosely, to what the businesses earn.
What this means for you
Section titled “What this means for you”You will not reliably know why today’s move happened, and you do not need to. A broad index already includes thousands of those arguments at once.
If a headline makes you want to trade, wait. Check whether your written plan, not the headline, called for a change. Your Investment Policy Statement is the document for that.
Common mistakes
Section titled “Common mistakes”Inventing a story for every up or down day.
Confusing a rising market with proof that you should buy more of what already went up.
Treating a falling price as a coupon to “average down” in a single company you have not researched.
Related pages
Section titled “Related pages”Educational content, not personalized financial, tax, or legal advice. No affiliate relationships. Figures are for tax year 2026 and change annually.Read the full disclaimer.