Financial Glossary
Clear definitions of the terms used across Arachnibull — plus a short “Arachnibull’s take” so the language sticks and connects to how we actually trade and size risk.
Call Option
A contract that gives the buyer the right to purchase the underlying asset at a fixed strike price before expiration. One standard equity call controls 100 shares.
Arachnibull’s take: “You’re renting upside. Small premium, large potential if the move arrives in time.”
Put Option
A contract that gives the buyer the right to sell the underlying at the strike before expiration. Used for downside protection or bearish speculation.
Arachnibull’s take: “Insurance you can also trade. When fear spikes, puts can move as violently as calls.”
Strike Price
The fixed price at which the option can be exercised.
Arachnibull’s take: “The finish line the underlying has to cross (or stay beyond) for the option to have intrinsic value.”
Premium
The price paid for an option contract. It is the maximum loss for a long option position.
Arachnibull’s take: “Your defined risk. Size positions by how much premium you’re willing to lose if the idea is wrong.”
Intrinsic Value
The amount by which an option is in-the-money. For a call: max(0, underlying price − strike). For a put: max(0, strike − underlying price).
Arachnibull’s take: “The part of the premium that is ‘real’ right now. Everything else is time and volatility value.”
Extrinsic / Time Value
The portion of an option’s premium that is not intrinsic value. It reflects time remaining and expected volatility.
Arachnibull’s take: “This is what theta erodes every day the big move doesn’t happen.”
Delta
The approximate change in option price for a $1 move in the underlying. Calls have positive delta; puts have negative delta. Ranges roughly from 0 to 1 (calls) or 0 to −1 (puts).
Arachnibull’s take: “How much ‘stock-like’ exposure the option currently has. Near-the-money options often sit around 0.50.”
Gamma
How fast delta itself changes as the underlying moves. High gamma means the option’s sensitivity can accelerate quickly.
Arachnibull’s take: “The fuel for parabolic moves. Short-dated, near-the-money options are high-gamma instruments.”
Theta
The daily decay in an option’s value due to the passage of time, all else equal. Usually expressed as a negative number for long options.
Arachnibull’s take: “The silent tax. Every day the move doesn’t happen, theta takes a bite.”
Vega
Sensitivity of the option price to a 1% change in implied volatility.
Arachnibull’s take: “When fear rises, option prices rise even if the underlying hasn’t moved yet. Vega is that channel.”
Implied Volatility (IV)
The market’s forecast of future volatility, embedded in option prices. Higher IV means more expensive options, all else equal.
Arachnibull’s take: “High IV means expensive options. Sometimes that’s justified by an upcoming event; sometimes it’s a trap.”
IV Rank / IV Percentile
Measures of how current implied volatility compares to its own history over a lookback period (often one year).
Arachnibull’s take: “Helps answer: are options cheap or expensive relative to this name’s own past, not just relative to other names.”
Open Interest
The number of outstanding option contracts that have not been closed or exercised.
Arachnibull’s take: “Rising OI at a strike often means fresh capital is expressing a view.”
Volume (Options)
The number of contracts traded in a given period. High volume relative to open interest can signal new positioning or heavy closing activity.
Arachnibull’s take: “Volume shows urgency; open interest shows commitment. Both together at a key level are more informative than either alone.”
3× Leveraged ETF
An ETF that seeks three times the daily return of its underlying index. Rebalanced daily and subject to volatility decay over multi-day periods.
Arachnibull’s take: “A tactical weapon, not a long-term holding. Respect the daily reset.”
Volatility Decay / Beta Slippage
The tendency of leveraged ETFs to lose value over time in volatile, non-trending markets because of daily rebalancing.
Arachnibull’s take: “This is why holding 3× products through chop is usually expensive even if the index ends roughly unchanged.”
Parabolic Return
Rapid, accelerating gains in an option (or leveraged product) when the underlying moves decisively in the right direction near expiration or during a strong trend.
Arachnibull’s take: “The outcome we model for — convex upside when timing and direction both align.”
Defined Risk
A position whose maximum loss is known at entry (e.g., long stock, long plain ETF, long options). Contrasts with undefined or hard-to-quantify risk.
Arachnibull’s take: “Prefer defined risk until process and psychology are proven. Size still matters — many small defined losses can still hurt.”
Invalidation Level
The price or condition at which the original thesis is considered wrong and the position should be exited or re-evaluated.
Arachnibull’s take: “Write it down before entry. Moving it further away after you’re already in is how small losses become large ones.”
Position Sizing
The process of deciding how much capital to allocate to an idea so that a full loss stays inside a predetermined risk budget.
Arachnibull’s take: “The primary risk control. Edge without sizing discipline eventually meets a losing streak that ends the game.”
Risk of Ruin
The probability that a series of losses reduces capital to a point where recovery is impractical or impossible under the same strategy.
Arachnibull’s take: “This is why small size + high-quality ideas compounds better than large size + high activity.”
Regime
The prevailing market environment (trending vs range-bound, high vs low volatility, risk-on vs risk-off). Different regimes reward different behaviors.
Arachnibull’s take: “Many large losses occur when a process that worked in one regime is applied unchanged in another.”
Breadth
Measures of how widely participation is distributed across stocks (e.g., % above the 50-day moving average, advance/decline line, new highs vs new lows).
Arachnibull’s take: “Expanding breadth supports holding leveraged risk longer. Narrowing leadership is a warning to tighten.”
Narrative + Setup
Arachnibull’s preferred process: a clear fundamental or macro story combined with a technical trigger, defined invalidation, and appropriate size.
Arachnibull’s take: “Story without price confirmation is opinion. Price without a story is often noise. Both together create higher-quality risk.”
Ready to put the language to work?