A wall of numbers
Pull up any stock on Yahoo Finance. You'll see a sidebar crammed with numbers: market cap, volume, P/E, 52-week range, shares outstanding, earnings date. Most people glance at the price and ignore the rest.
But here's the question: if two stocks both went up 5% today, are they the same trade?
One might be a $2 trillion giant moving on massive institutional rotation. The other might be a $500 million company where a single fund's buy order pushed the price. The numbers in that sidebar tell you which is which — and whether you should care.
Let's decode them from first principles.
Market cap — how big is this company?
Market cap = share price × total shares outstanding.
That's it. It's not revenue, not profit, not assets. It's simply what the market collectively believes this company is worth right now.
Why does it matter to you? Size determines behavior. A $2 trillion stock (Apple, Microsoft) moves like an ocean liner — slowly, predictably, hard to manipulate. A $500 million stock moves like a speedboat — fast, volatile, responsive to a single buyer or seller.
Neither is better. But they require different expectations.
Float vs shares outstanding — who can actually trade?
Shares outstanding is the total number of shares that exist. Float is the subset available for public trading — excluding shares locked up by insiders, institutions with long-term holds, and restricted stock.
Think of it this way: shares outstanding is how many seats exist in a stadium. Float is how many are actually available on StubHub right now.
A low float stock (say, 10 million shares) can move violently on relatively small volume. A stock with 5 billion shares floating barely flinches. When you see a stock spike 20% in a day, check the float. It's almost always small.
Volume — the lie detector
You already know price tells you what happened. Volume tells you who showed up.
Two numbers matter here:
Average daily volume — the stock's normal activity level, usually measured over 50 or 90 days. This is the baseline.
Today's volume — what's happening right now.
The relationship between these two is everything. A stock breaking out on 3× its average volume? Institutions are involved. That same breakout on half its average volume? Probably noise. No conviction behind the move.
Volume doesn't lie because it represents real money changing hands. Price can be pushed around by a few aggressive orders. But sustained high volume means many participants agree on the direction — or disagree violently enough to create a trade.
P/E ratio — what are you paying for?
Price-to-Earnings ratio = share price ÷ earnings per share.
Strip away the jargon: P/E answers one question — how many years of current earnings would it take to "pay back" the stock price?
A P/E of 20 means you're paying 20 years' worth of today's earnings for ownership. A P/E of 100 means you're paying a century's worth — or more accurately, you're betting earnings will grow dramatically.
High P/E doesn't mean "expensive." It means the market expects rapid growth. Low P/E doesn't mean "cheap." It might mean the market expects earnings to decline.
P/E is a consensus expectation about the future, priced in today. Nothing more.
52-week high and low — memory and anchoring
Humans anchor to round numbers and extremes. So do markets — because markets are humans.
The 52-week high matters because every person who bought in the last year is profitable when price approaches it. There are no "trapped" holders above waiting to sell and get out at breakeven. That's why breakouts above the 52-week high often continue — there's no overhead supply.
The 52-week low is the opposite. Everyone who bought in the last year is underwater. Some capitulate. Others hold and hope. Approaching the low creates a psychological battleground.
When you see a stock near its 52-week high on rising volume, that's strength. Near its low on rising volume? That's either capitulation or a bottom — context determines which.
Earnings date — the known unknown
Every quarter, companies report earnings. The date is known in advance. What they'll report is not.
Earnings dates matter because they inject volatility. Options pricing spikes before earnings. Stocks can gap 10-20% overnight on a surprise. No chart pattern, no technical indicator can predict an earnings surprise.
Know when earnings are coming. Decide before the event whether you want to hold through it or not. "I'll decide after I see the number" is a plan that leads to panic decisions at the worst possible moment.
Where to find all of this — for free
You don't need a Bloomberg terminal. Two free sources cover everything above:
Yahoo Finance (finance.yahoo.com) — Pull up any ticker. The "Statistics" tab has everything: market cap, float, average volume, P/E, 52-week range, earnings date. The "Chart" tab gives you price and volume. It's comprehensive and reliable.
Finviz (finviz.com) — The stock screener is the real power here. You can filter the entire market by any combination of these metrics. Want all stocks with a float under 20 million and volume above 1 million? Three clicks. Finviz also shows a snapshot view for any ticker with all key stats on one screen.
Both are free. Both update in real-time during market hours. Start with Yahoo Finance for individual stock research. Use Finviz when you want to scan across the market.
Try it yourself
Look up any S&P 500 stock on Yahoo Finance. Find its average daily volume and today's volume. Is today's volume higher or lower than average? If it's significantly different, check the chart — did price make an unusual move? Notice how volume and price movement connect.
PaperEdge tracks all of this automatically — join free to follow along.
Next: Introduction to Options Data →