Delta, Theta, Gamma, Vega, Rho — the language of options risk management, translated to binary event contracts. Where the analogy holds perfectly, where it breaks, and why the framework is still the best way to think about PM positions.
Prediction market contracts are not options. They don't have strike prices, there's no Black-Scholes formula, and there's no continuous market-maker delta-hedging the book. But the Greeks — the framework that options traders use to decompose risk into measurable components — translate to binary event contracts with surprising precision.
The reason is structural: both options and PM contracts are derivatives whose value depends on an uncertain future event. Options derive value from whether a stock will be above or below a price. PM contracts derive value from whether an event will occur or not. The math is different, but the risk dimensions are the same.
Thinking in Greeks forces you to ask the right questions before entering a trade: how sensitive is my position to a probability shift? How fast is time eroding my value? Am I exposed to volatility expansion or compression? These questions matter whether you're trading SPY calls or Bundesliga match contracts.
In options: delta measures how much the option price changes per $1 move in the underlying stock.
In prediction markets: delta measures how much the contract price changes per 1 percentage point shift in the true underlying probability. For binary contracts, this is approximately 1:1 in the mid-range — a contract at 50¢ moves roughly 1¢ for every 1pp shift in perceived probability. But the relationship is nonlinear at the extremes.
A contract at 5¢ has low delta in absolute terms but enormous delta in percentage terms. A 5pp probability increase (from 5% to 10%) doubles the contract price from 5¢ to 10¢. The same 5pp shift on a 50¢ contract is a 10% move. This asymmetry is why cheap contracts are so tempting — and so dangerous.
Contracts near 50¢ have the highest absolute delta — they're the most responsive to new information. Contracts near 0¢ or 100¢ have low absolute delta but can move violently on a single catalyst. When you see a 5¢ contract jump to 15¢ on one news event, you're seeing low-delta becoming high-gamma (see below).
How to use it: If you want maximum sensitivity to an information edge, trade contracts near 50¢. If you want asymmetric payoffs (small risk, large potential gain), trade cheap contracts — but understand that most of them will expire at $0. This is the fundamental trade-off the Favourite-Longshot Bias (304) exploits.
Covered in depth in article 306. The summary:
In options: theta is the daily erosion of option premium as expiry approaches.
In prediction markets: theta exists only for "will X happen by [date]?" contracts. Every day without the triggering event reduces the number of remaining catalysts and pushes the contract price toward $0. Contracts without a deadline ("who wins?") have zero theta.
Measurable as: the daily price decline you'd expect if no new information arrives. On a "Fed cuts by June" contract at 40¢ with four remaining meetings, theta is roughly the contract price divided by the number of remaining catalyst events: ~10¢ per non-event. But theta accelerates as the deadline approaches, just as it does for options — the last meeting carries disproportionate weight.
How to use it: If you're buying Yes on a deadline contract, you're paying theta. Factor it into your sizing — your edge needs to exceed theta to be profitable. If you're selling (buying No), theta works for you. The passage of uneventful time is your income stream.
In options: gamma measures how fast delta changes as the underlying moves. High gamma means your delta is unstable — small moves in the underlying cause large changes in your exposure.
In prediction markets: gamma is highest for contracts near the extremes (very cheap or very expensive). A contract at 5¢ has low delta but extreme gamma — one piece of news can move it from 5¢ to 25¢, fundamentally changing the position's character. A contract at 50¢ has moderate gamma — it responds proportionally to information.
This explains why cheap contracts are both the most alluring and the most dangerous positions in prediction markets:
| Contract price | Delta | Gamma | Behaviour |
|---|---|---|---|
| 5¢ | Low (absolute) | Very high | Dormant until catalyst hits, then explosive. Most expire at $0. |
| 25¢ | Moderate | High | Responsive to news. Good risk/reward if edge is real. |
| 50¢ | Maximum | Moderate | Most information-sensitive. Moves proportionally. |
| 75¢ | Moderate | High | Moving toward certainty. Vulnerable to surprise reversal. |
| 95¢ | Low (absolute) | Very high | Seemingly safe, but a single adverse event causes massive % loss. |
How to use it: Be aware of your portfolio's gamma exposure. A portfolio of 5¢ and 95¢ contracts looks diversified but has extreme gamma in both directions — it's actually a high-volatility bet. A portfolio concentrated around 30¢–70¢ has more manageable gamma and more predictable behaviour.
In options: vega measures sensitivity to changes in implied volatility. When uncertainty rises, options become more expensive (volatility premium).
In prediction markets: vega measures sensitivity to changes in the market's confidence about the outcome — not the probability itself, but the uncertainty around that probability. A contract at 50¢ could represent "we genuinely have no idea" (high vega) or "we're very confident it's a coin flip" (low vega). The price is the same; the behaviour is completely different.
High-vega contracts have wider bid-ask spreads, more erratic price movements, and are more susceptible to narrative-driven swings. Low-vega contracts (markets with strong consensus) are tight, stable, and hard to find edge in.
You can't directly observe "implied volatility" on a PM contract the way you can for options. But you can proxy it: look at the bid-ask spread (wider = higher uncertainty), the price history (more volatile = higher vega), and the information environment (upcoming catalysts = vega expansion). A Bundesliga match contract 3 days before kickoff has lower vega than the same contract 3 weeks out — more is known.
How to use it: If you have an information edge, high-vega contracts are where you want to be — the uncertainty creates mispricing. If you're trading mechanically without a strong view, avoid high-vega contracts — the bid-ask spread and price instability will eat your capital.
In options: rho measures sensitivity to interest rate changes. Usually negligible for short-dated options but matters for LEAPS.
In prediction markets: rho represents the opportunity cost of locked capital. A contract at 40¢ that resolves in 6 months ties up your capital for half a year. In a 5% interest rate environment, that capital could earn ~2.5% risk-free. This means your edge needs to exceed not just the platform fee but also the opportunity cost.
Rho matters more in prediction markets than most traders realise because of the binary structure. In equities, you can always sell. In PM contracts, liquidity may be thin, and your capital might be effectively locked until resolution.
The math: For a 40¢ contract resolving in 6 months, your opportunity cost at 5% risk-free rate is approximately 40¢ × 2.5% = 1¢. Not huge for a single contract, but across a portfolio of 20 positions averaging $500 each, that's $250/year in opportunity cost. Enough to turn a marginal edge negative.
How to use it: In high-rate environments, favour shorter-duration contracts. Long-dated contracts need bigger edges to overcome rho. This is why political season contracts (6-12 months) are structurally harder to profit from than weekly sports contracts, even with the same analytical edge.
Intellectual honesty requires flagging where the Greeks-for-PMs framework has limits:
No continuous pricing model. Options have Black-Scholes (or more sophisticated models) that calculate exact Greek values from observable inputs. PM contracts have no equivalent closed-form model. The "Greeks" described here are intuitions and approximations, not precise calculations.
No hedging. Options Greeks enable delta-neutral strategies, gamma scalping, and volatility trading through hedging. PM contracts can't be hedged in the same way — you can't short one outcome to offset another in a mathematically precise manner. (You can buy No, but that's a directional trade, not a hedge.)
Discrete events, not continuous distributions. Options expire based on where a stock price lands on a continuous scale. PM contracts resolve based on discrete events (win/lose, yes/no). This means the "underlying" moves in jumps, not smooth curves — making Greek-based risk models noisier.
Information asymmetry is the dominant factor. In liquid equity options markets, Greeks explain most of the price behaviour. In PM markets, information asymmetry often overwhelms all Greek-based analysis. A single insider who knows the outcome can move the price regardless of theta, gamma, or vega.
The real power of the Greeks framework isn't in analysing individual contracts — it's in understanding your portfolio's aggregate exposure:
What's my total delta? (Am I net long or short probability across all positions?)
What's my theta burn? (How much am I paying per day in time decay across deadline contracts?)
Where's my gamma concentration? (Am I overexposed to extreme-price contracts that could swing violently?)
What's my vega exposure? (Am I positioned in high-uncertainty markets where a consensus shift could move everything at once?)
What's my capital lock-up and rho cost? (Am I tying up too much capital in long-dated contracts?)
This portfolio-level thinking is what separates systematic traders from gamblers. It's also the foundation for the Portfolio Builder tool (coming in Phase 4).