Why Stocks Move

Nobody has time to read dozens of scattered market headlines. These guides explain the likely reason a stock is moving today in one clear, fast read.

Start with a research path

Seven topic clusters, each built around a different market mechanism

7 evidence maps

01Why Stocks Move Around Earnings and GuidanceA practical research path for earnings beats, misses, whisper numbers, guidance changes, and conference-call reversals.Open evidence map →
02How Inflation, Jobs, the Fed, Yields, and the Dollar Move StocksFollow the chain from an economic surprise to rates, currencies, equity valuations, and sector leadership.Open evidence map →
03How Options, Auctions, and Dealer Hedging Can Move StocksUnderstand open interest, expiration, gamma exposure, closing auctions, triple witching, and late-session reversals without turning one metric into a prediction.Open evidence map →
04How Insider Trades, 13F Filings, Congressional Disclosures, and Short Interest Affect StocksRead ownership disclosures with the right transaction date, reporting lag, position size, and liquidity context.Open evidence map →
05Why Offerings, Buybacks, Spinoffs, Convertibles, and Merger Rumors Move StocksTranslate legal transaction terms into dilution, share supply, balance-sheet effects, deal probability, and forced flows.Open evidence map →
06Why Bank, Oil, Semiconductor, Biotech, Retail, and REIT Stocks Move TogetherBuild an exposure map before using one company, commodity, rate move, or regulatory event as a read-through for an entire sector.Open evidence map →
07Why Stocks Move Before the Open and After the CloseInterpret premarket and after-hours prices through volume, spreads, news timing, the conference-call clock, and the return of regular-session liquidity.Open evidence map →

Research library71 focused signal guides7 research clusters

Research cluster

Earnings & expectations

Reports, guidance, calls, and the expectations behind the reaction.

11 guides

Guide 005Earnings & expectations
Why Do Stocks Rise After Earnings?
A stock does not rise after earnings just because the headline number beat consensus.
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Guide 006Earnings & expectations
Why Do Stocks Fall After Earnings?
A company can post a quarter that looks fine to a casual reader and still lose 15% before the next opening bell.
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Guide 007Earnings & expectations
How Do Analyst Upgrades Affect Stocks?
An analyst upgrade does not move a stock because one person said “buy” on television.
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Guide 030Earnings & expectations
How Do Analyst Downgrades Move Stock Prices?
A single analyst at Goldman Sachs or Morgan Stanley changes a rating from "Buy" to "Neutral" — and a stock drops 8% before lunch.
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Guide 031Earnings & expectations
Why Does Earnings Guidance Move Stocks More Than the Actual Results?
The company beats earnings by 20%.
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Guide 033Earnings & expectations
How to Read an Earnings Report Before It Moves a Stock
An earnings release hits at 4:05 PM.
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Guide 036Earnings & expectations
Why Do Stocks Drop on Good Earnings?
It is one of the most frustrating experiences in investing: a company you own reports record profits, beats analyst expectations, a…
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Guide 041Earnings & expectations
Do Stocks Usually Go Up Before Earnings?
A stock can rally or sell off days before it reports without a single new number from the company.
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Guide 042Earnings & expectations
Why Did a Stock Rise After Missing Revenue Estimates?
A revenue miss sounds automatically negative, but the market values the future earnings path rather than one headline metric.
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Guide 043Earnings & expectations
How Do Earnings Call Comments Move a Stock Price?
The press release gives investors the numbers; the earnings call explains whether those numbers can continue.
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Guide 044Earnings & expectations
Why Can a Stock Fall After Raising Guidance?
Raising guidance is positive in isolation, but stocks do not trade in isolation.
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Research cluster

Macro & rates

Inflation, policy, yields, currencies, and their cross-market effects.

10 guides

Guide 008Macro & rates
How Do Interest Rates Affect Stocks?
Interest rates are the market’s gravity setting.
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Guide 022Macro & rates
Why Do Tech Stocks Fall When Interest Rates Rise?
In 2022, the Federal Reserve raised interest rates from near zero to over 5%.
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Guide 028Macro & rates
How Do Federal Reserve Decisions Move the Stock Market?
Eight times a year, a group of officials meets in Washington D.C.
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Guide 029Macro & rates
How Does Inflation Affect Stock Prices?
In 2021, U.S.
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Guide 045Macro & rates
How Does CPI Data Move Stock Prices?
The Consumer Price Index is not just an inflation headline.
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Guide 047Macro & rates
What Is an FOMC Meeting and Why Do Stocks Move on Fed Days?
The Federal Open Market Committee sets US monetary policy, but the market reaction rarely comes from the rate decision alone.
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Guide 048Macro & rates
Why Does a Strong Dollar Affect Stocks?
The dollar changes the value of overseas sales when global companies convert revenue back into US dollars.
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Guide 049Macro & rates
Why Do Stocks Fall When Bond Yields Rise?
Bond yields are the price of money across the economy.
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Guide 064Macro & rates
Why Do Bank Stocks Move With Interest Rates?
Interest rates shape a bank’s lending income, deposit costs, and the value of its securities portfolio.
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Guide 065Macro & rates
Why Do Oil Stocks Move With Oil Prices?
Crude prices feed directly into the revenue and cash-flow outlook for many energy producers, so oil equities often react when the c…
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Research cluster

Market structure

Options, liquidity, trading sessions, flows, and price mechanics.

20 guides

Guide 009Market structure
What Is a Short Squeeze?
A short squeeze looks irrational only if you ignore the mechanics.
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Guide 011Market structure
Why Is a Stock Going Up With No News?
A stock can rise hard even when there is no obvious headline on your screen.
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Guide 015Market structure
What Is a Market Maker and How Do They Affect Stock Prices?
Every time you buy or sell a stock instantly — without waiting for another investor to take the other side — a market maker made th…
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Guide 016Market structure
What Is a Stock Float and Why Does It Matter for Price Moves?
Two stocks can have the same market cap and the same news catalyst — but one moves 3% while the other moves 30%.
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Guide 017Market structure
What Is a Stock Gap and Why Do Stocks Open Higher or Lower Than They Closed?
You checked a stock at 4 PM — it closed at $45.
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Guide 018Market structure
What Is Index Rebalancing and Why Does It Move Stock Prices?
Every quarter, without any company news, without any earnings release, billions of dollars pour into and out of specific stocks — n…
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Guide 021Market structure
Why Are After-Hours Stock Moves So Exaggerated?
You check your portfolio at 5 PM and your stock is up 22% after an earnings beat.
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Guide 027Market structure
How Does Dark Pool Trading Affect Stock Prices?
Roughly 40% of U.S.
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Guide 038Market structure
Why Do Stocks Halt Trading and What Happens Next?
You look at your brokerage app during a wild market move and notice the price has stopped updating, and the buy/sell buttons are di…
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Guide 039Market structure
Why Is a Stock Flat on High Volume?
A stock trades 10 times its average daily volume, but the price barely moves, closing flat for the day.
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Guide 050Market structure
What Is Open Interest in Options and Why Does It Matter for Stocks?
Open interest measures outstanding options positions, not daily trading volume.
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Guide 051Market structure
How Does Options Expiration Affect Stock Prices?
When options expire, traders close, roll, or exercise positions while dealers rebalance the hedges that supported those contracts.
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Guide 052Market structure
What Is Gamma Exposure and How Can It Move a Stock?
Gamma exposure describes how quickly an options hedge must change as a stock price moves.
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Guide 053Market structure
Why Do Stocks Move So Much at the Market Close?
The final minutes of trading concentrate a large share of daily institutional activity.
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Guide 058Market structure
What Is the Short Interest Ratio and Why Does It Matter?
The short interest ratio, often called days to cover, estimates how many days of normal trading volume short sellers would need to…
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Guide 059Market structure
What Is Days to Cover in Stocks?
Days to cover divides shares sold short by average daily volume.
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Guide 068Market structure
What Is Premarket Trading and Why Do Prices Move Before the Open?
Premarket trading lets eligible investors trade before the normal US session begins.
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Guide 069Market structure
What Is After-Hours Trading and Why Do Stocks Move Then?
After-hours trading lets participants respond to news after the regular market closes.
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Guide 070Market structure
Why Do Some Stocks Have Wide Bid-Ask Spreads?
The bid-ask spread is the gap between what buyers will pay and sellers will accept.
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Guide 071Market structure
Why Are Low-Volume Stocks Risky for Investors?
Low trading volume means fewer buyers and sellers are available when you need to trade.
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Research cluster

Corporate actions

Buybacks, dividends, offerings, mergers, splits, and capital events.

8 guides

Guide 019Corporate actions
What Is a Stock Buyback and How Does It Affect Share Price?
A company that buys its own shares on the open market is doing something counterintuitive: spending cash to own itself.
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Guide 024Corporate actions
Why Do Stocks Drop on the Ex-Dividend Date?
You own a dividend stock.
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Guide 032Corporate actions
What Happens to a Stock's Price During a Merger or Acquisition?
A company you own just announced it's being acquired at a 35% premium to the current stock price.
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Guide 037Corporate actions
What Is a Stock Offering and Why Does the Price Drop?
When a company announces it is raising capital through a stock offering, the stock price almost always drops immediately, sometimes…
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Guide 040Corporate actions
What Happens When a Stock Is Delisted from a Major Exchange?
A company fails to meet listing requirements, and its stock is delisted from the NYSE or Nasdaq.
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Guide 060Corporate actions
What Is an At-the-Market Offering and Why Does It Affect a Stock?
An at-the-market, or ATM, offering allows a company to sell new shares gradually at prevailing market prices.
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Guide 061Corporate actions
Why Do Stocks Move on Merger Rumors?
A credible merger rumor can cause a target company’s stock to jump because investors begin pricing the chance of a takeover premium.
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Guide 062Corporate actions
Why Does a Stock Drop After a Convertible Notes Offering?
Convertible notes give investors debt that may convert into shares later.
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Research cluster

Sectors & themes

How shared industry exposures turn one catalyst into a group move.

4 guides

Guide 020Sectors & themes
What Is Sector Rotation and Why Does Money Move Between Industries?
In 2022, technology stocks fell 30–40% while energy stocks rose 50–60%.
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Guide 023Sectors & themes
Why Do Defensive Stocks Rise When the Rest of the Market Falls?
When the S&P 500 fell 25% in 2022, utility stocks barely moved.
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Guide 066Sectors & themes
Why Do Semiconductor Stocks Move Together?
Chip companies can have different products, but they share major demand drivers such as cloud spending, consumer electronics, autom…
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Guide 067Sectors & themes
Why Do Biotech Stocks Move So Much on FDA News?
For many biotech companies, one clinical-trial result or FDA decision can change the entire value of the business.
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Research cluster

Behavior & decision-making

Fear, FOMO, volatility, and keeping a process during fast markets.

3 guides

Guide 004Behavior & decision-making
Why Are Stocks Volatile?
A stock does not become volatile because investors suddenly lose discipline.
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Guide 014Behavior & decision-making
How Market Sentiment Moves Stocks
Markets do not move on facts alone.
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Guide 035Behavior & decision-making
Why Do Stocks Almost Always Recover After a Market Crash?
Market crashes feel final while they are happening.
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Research cluster

Case studies & company moves

Recognizable market moments and the mechanics that made them matter.

15 guides

Guide 001Case studies & company moves
Why Do Stocks Go Up?
A stock can sit flat for weeks and then jump 8% in a single morning because one new fact changed what the market thinks the busines…
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Guide 002Case studies & company moves
Why Do Stocks Go Down?
A stock does not need catastrophic news to fall hard.
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Guide 003Case studies & company moves
What Makes Stocks Move Fast?
Most stocks spend their days drifting.
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Guide 010Case studies & company moves
Why Do Stocks Crash Suddenly?
A stock crash usually feels sudden only because the market stops offering you a graceful exit.
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Guide 012Case studies & company moves
How Does News Affect Stock Prices?
News moves stocks only when it changes what investors think the future looks like.
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Guide 013Case studies & company moves
What Causes Volume Spikes in Stocks?
A price move tells you direction.
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Guide 025Case studies & company moves
Why Do Stocks Jump When They're Added to the S&P 500?
Getting added to the S&P 500 doesn't make a company more profitable.
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Guide 026Case studies & company moves
How Do ETF Inflows and Outflows Move Individual Stock Prices?
When investors pour money into the XLK technology ETF, every stock in that ETF gets bought — Apple, Microsoft, Nvidia, and hundreds…
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Guide 034Case studies & company moves
How to Spot a Stock Catalyst Before It Happens
Most retail investors find out about a catalyst after the stock has already moved.
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Guide 046Case studies & company moves
Jobs Report Market Reaction: How Does the Jobs Report Move Stocks?
Payrolls, unemployment, and wage growth tell investors whether the economy is speeding up, slowing down, or overheating.
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Guide 054Case studies & company moves
Why Does Insider Buying Move a Stock Price?
When an executive buys shares with personal money, investors often treat it as a signal of confidence in the company’s value or out…
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Guide 055Case studies & company moves
Why Does Insider Selling Move a Stock Price?
Insider sales attract attention because executives know their businesses closely, but a sale is not automatically a warning.
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Guide 056Case studies & company moves
How Do 13F Filings Affect a Stock Price?
Quarterly 13F filings show the US equity positions of many large investment managers.
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Guide 057Case studies & company moves
Why Do Congressional Trades Move Stock Prices?
Congressional trading disclosures can draw attention because investors may see a lawmaker’s transaction as a clue about policy expo…
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Guide 063Case studies & company moves
Why Do Stocks Drop After a Secondary Offering?
A secondary offering increases the amount of stock available to buyers, either through new company shares or sales by existing hold…
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WhyStockMove provides educational market research only. Nothing on this site is personalized financial advice or a recommendation to buy or sell any security. Verify information independently and consult a qualified professional for advice about your situation.