A leveraged ETF promises a multiple of an index’s return for one day. A 3x fund on the Nasdaq-100 aims to rise 3 percent when the index rises 1 percent on a given day, and to fall 3 percent when it falls 1 percent. An inverse fund does the same with a minus sign. The key words are “for one day”. Over a week, a month or a year the fund can return far more or far less than three times the index, and in a choppy market it can lose money while the index goes nowhere.

Market breadth measures how many stocks are taking part in a move. An index like the S&P 500 is weighted by market value, so a handful of giant companies can push it to a record while most of its members go nowhere or fall. Breadth indicators strip the weighting out. They count stocks: how many rose, how many fell, how many hit new highs, how many sit above a moving average.

Short interest is the number of a company’s shares that have been sold short and not yet bought back. A short seller borrows shares, sells them, and hopes to buy them back later at a lower price before returning them to the lender. Until that buyback happens, the position is open, and it shows up in the short interest count. Investors watch the figure for two reasons. It tells you how many professional skeptics are betting against a stock.

Circuit breakers are the rules that stop trading when prices move too far, too fast. US stock markets have two main layers. Market-wide circuit breakers halt every stock and options exchange when the S&P 500 falls 7%, 13% or 20% in a day. Limit Up-Limit Down (LULD) bands work one stock at a time, pausing trading for five minutes when a single name breaks out of its allowed price range. On top of those sit ordinary trading halts that exchanges call for news, plus a short-sale restriction that kicks in after a 10% drop.

Wall Street runs on two languages. One is formal: financial statements, analyst reports, SEC filings. The other is the fast shorthand traders use when they talk about what is actually happening in the market. A headline might say a company “delivered a strong print but the stock faded as investors digested cautious guidance.” That sounds complicated. It means the reported numbers were good, the stock went up at first, and then investors focused on weaker forward expectations and the price came back down.

The rule that has defined active retail trading for a quarter century is gone. On April 20, 2026, FINRA published Regulatory Notice 26-10, adopting new intraday margin standards under Rule 4210 that replace the day trading margin framework in its entirety — including the pattern day trader designation and the $25,000 minimum equity requirement that came with it. The changes took effect June 4, 2026, with brokers permitted an 18-month phase-in through October 20, 2027.

A trading account with a subscription product to sell recently posted a four-tier VIX framework designed to be screenshotted and bookmarked: buy aggressively above 35, scale in between 25 and 35, hold between 15 and 25, and reduce exposure below 15. The pitch was simple and confident — “this is all you need to make millions.” The VIX sits at roughly 16 today, comfortably in the “hold” zone the post describes, which is one of the few things about it that checks out.

Markets are priced by people, and people swing between two emotions: the fear of losing money and the greed to make more of it. The CNN Fear & Greed Index is an attempt to compress that emotional state into a single number between 0 and 100 — 0 being maximum fear, 100 being maximum greed, 50 being neutral. It is one of the most-watched sentiment gauges in retail and professional finance, and one of the most misunderstood.

A working reference for the vocabulary of financial markets — organized by domain, not alphabetically. Definitions are written for investors, analysts, financial journalists, and informed participants who need precision without the padding of a textbook. Market Structure Equity Ownership interest in a company, represented by shares of stock. Equity holders are residual claimants — they receive what remains after all creditors and obligations are satisfied. Common equity carries voting rights; preferred equity has priority in distributions but typically limited voting power.