Handbook & Clock

Market hours, holidays, and plain-English answers to the questions traders ask.

Prices delayed at least 15 minutes unless marked live. Times Eastern. Educational and informational only; not investment advice.

Trader’s handbook

Plain-English answers to what new traders ask and experienced ones double-check. General education only, not advice; rules differ by broker and change over time.

Orders

Market order: Buy or sell now at the best price available. Fast, but in a thin or fast market you can get a worse price than the last one you saw.
Limit order: Buy at or below, or sell at or above, a price you set. You control the price but may not get filled.
Stop (stop-loss): Becomes a market order once the price touches your stop. It limits nothing in a gap: if a stock opens far below the stop, you sell at the open.
Stop-limit: Becomes a limit order at the stop. Protects the price, but may never fill if the price runs through it.
Trailing stop: A stop that follows the price up by a set amount or percent and stays put when it falls.
Time in force: Day orders expire at the close. Good-’til-canceled (GTC) orders stay open, usually up to a broker limit such as 90 days. Many brokers only fill extended-hours orders that are limit orders.

Prices and trading

Bid, ask, spread: The bid is the best price buyers offer; the ask is the best price sellers want. The gap is the spread, a hidden cost every round trip. Wider spreads mean thinner trading.
Volume and liquidity: Volume is how many shares changed hands. Higher volume usually means tighter spreads and easier exits. A move on unusually heavy volume carries more information than one on light volume.
Gap: When a price opens well away from the prior close, usually after news overnight. Stops do not protect you inside a gap.
Volatility: How much a price typically swings. Annualized volatility of 20% means a one-standard-deviation year is roughly ±20%. Ticker pages show it measured from past closes.
Beta: How much a stock has tended to move with the S&P 500. 1.0 moves in step, 2.0 about twice as much, 0.5 half. It describes the past, not the future.
Drawdown: The fall from a previous peak. A 50% drawdown needs a 100% gain to get back to even.

Company numbers

Market value (cap): Share price times shares outstanding: what the market says the whole company is worth.
P/E ratio: Price divided by a year of earnings per share. A high P/E means investors are paying up for expected growth, or earnings are temporarily low.
Earnings and guidance: Companies report each quarter. Prices often move more on guidance (what management expects next) than on the quarter itself.
Dividend and ex-dividend date: A dividend is cash paid per share. To receive it you must own the shares before the ex-dividend date; on that date the price usually drops by about the dividend.
Dilution and buybacks: New shares shrink each holder’s slice (dilution); buybacks do the opposite. Ticker pages flag filings that can add shares.
Short interest: Shares sold short and not yet bought back. High short interest means many traders expect a fall, and can fuel sharp rises when they rush to cover.

Accounts and rules (U.S.)

Settlement (T+1): U.S. stock trades settle one business day after the trade. In a cash account, selling before purchases settle can trigger a good-faith violation.
Margin: Borrowing from your broker to buy more. It magnifies gains and losses, charges interest, and a margin call can force sales at the worst time. You can lose more than you put in.
Pattern day trader rule: Under current FINRA rules, four or more day trades in five business days in a margin account requires $25,000 of equity. Check your broker; FINRA has proposed changes.
Wash sale: Selling at a loss and buying the same or a substantially identical security within 30 days before or after means the loss cannot be claimed yet for U.S. taxes.
Options in one paragraph: A call is the right to buy at a set price by a date, a put the right to sell. Buyers can lose the whole premium; sellers of uncovered options can lose far more. Prices rise before events like earnings because of expected moves (implied volatility).
SIPC: Protects up to $500,000 per customer (including $250,000 cash) if a member brokerage fails. It does not protect against market losses.

Risk basics

Position size: Decide in advance how much you can lose on one idea. Many traders risk a small, fixed slice of the account per trade.
Concentration: One holding above roughly 10–20% of a portfolio can dominate results. The watchlist’s concentration check shows your weights in your browser only.
Diversification: Holdings that do not all move together reduce swings. Many stocks in one sector are less diversified than they look.
Fees and taxes: Spreads, fund fees and short-term capital gains (taxed as ordinary income in the U.S.) quietly reduce returns. Holding over a year usually qualifies for lower long-term rates.

More: SEC Investor.gov glossary, FINRA investor education, SIPC.