Market Data

Every candlestick packs four numbers into one compact shape: the open (where the price started), the close (where it ended), the high (the peak), and the low (the trough). The thick "body" shows the range between open and close, while the thin "wicks" extend to the day's extremes. Think of each candle as a short story about the fight between buyers and sellers during that time period.

A green candle means the close was higher than the open — buyers won. A red candle means the close was lower — sellers won. The longer the body, the more decisive the victory. A long upper wick tells you the price tried to climb higher but got rejected back down. A long lower wick means it tried to fall further but buyers stepped in to support it.

Once you can read these shapes, a price chart stops being a random squiggle and starts telling a story. You can spot momentum, hesitation, and turning points — all from the anatomy of a single candle.

Every stock has two prices at any moment: the bid (the highest price someone is willing to pay) and the ask (the lowest price someone is willing to sell for). The gap between them is the bid-ask spread — think of it as the cost of trading right now instead of waiting. Highly liquid stocks like Apple might have a spread of just one cent, while a thinly traded penny stock could have a spread of 10 cents or more. That spread is money out of your pocket every time you trade.

The order book is the queue of all pending buy and sell orders at various prices. Bids stack up below the current price (buyers waiting for a deal), and asks stack up above it (sellers waiting for a premium). When you place a market order, you don't just get the best price — your order eats through the book level by level. A 100-share order might fill instantly at the best ask, but a 50,000-share order will blow through multiple levels and pay progressively worse prices. That difference is slippage, and it's why large institutional traders break orders into smaller pieces.

You hear "Apple is $230 a share" and "GameStop is $25 a share" and think Apple must be worth more. But share price on its own is meaningless — it's like comparing two pizzas by the price of a single slice without knowing how many slices each has. What actually matters is market capitalization: the share price multiplied by the total number of shares outstanding. That gives you the market's answer to "how much is this entire company worth?"

Companies are grouped into categories by their market cap: Mega Cap (>$200B) are the tech giants and global conglomerates, Large Cap ($10–200B) are well-established household names, Mid Cap ($2–10B) are growing companies that have proven themselves, Small Cap ($300M–2B) are younger or niche players, and Micro Cap (<$300M) are the smallest publicly traded companies. A stock's cap category tells you a lot about its risk profile, liquidity, and the kind of investor it attracts.