An arbitrageur is a trader or firm that tries to profit from relative pricing gaps while managing execution, funding, and convergence risk.
An arbitrageur is a trader, fund, dealer, or firm that attempts to profit from pricing differences between related assets, contracts, venues, currencies, or cash flows. The role is not simply finding a sure thing; it involves building offsetting positions and managing the risks that can prevent prices from converging as expected.
Arbitrageurs can help align prices across markets, but they also face practical limits: capital, borrow availability, margin, settlement, speed, liquidity, regulation, and model error.
| Activity | Why it matters |
|---|---|
| Identify related prices | Finds instruments that should be connected by contract, economics, or model. |
| Build offsetting positions | Reduces some directional exposure while retaining spread or basis exposure. |
| Finance and margin the trade | Determines whether the trade can survive before convergence. |
| Monitor hedge ratios | Keeps the position aligned as prices, volatility, and contract terms change. |
| Manage exits | Converts theoretical edge into realized profit or controlled loss. |
| Type | Common strategy | Main risk |
|---|---|---|
| Cross-market arbitrageur | Buys and sells equivalent instruments across venues. | Latency, fees, settlement, and partial fills. |
| Merger Arbitrage trader | Trades deal spread between target price and consideration. | Deal break, antitrust, financing, and timing risk. |
| Convertible Arbitrage trader | Buys convertible security and hedges equity or credit exposure. | Volatility, credit, borrow, and hedge-model risk. |
| Statistical Arbitrage trader | Trades modeled mean reversion or factor-neutral spreads. | Model decay, crowding, costs, and regime shifts. |
A stock trades on two venues with a visible price difference. An arbitrageur might try to buy on the cheaper venue and sell on the more expensive venue. The opportunity only exists if the trader can execute both legs, handle fees and settlement, avoid failed delivery, and keep the spread after costs.
If one leg fills and the other does not, the arbitrageur becomes directionally exposed.
| Evidence | Why it matters |
|---|---|
| Strategy mandate | Distinguishes market making, hedging, statistical arbitrage, and event-driven trading. |
| Position and hedge report | Shows whether the book is actually hedged or only described as hedged. |
| Borrow and financing terms | Short positions, leverage, and carry cost can dominate results. |
| Liquidity and slippage | Determines whether the edge can be captured at trade size. |
| Risk limits and stop rules | Shows how much convergence delay the book can tolerate. |
| Post-trade attribution | Separates spread capture from market beta, factor exposure, or luck. |