# Mark, index and last price: different numbers with different jobs

Last price is the price of a recent completed trade. An index or oracle price is a reference assembled under a published method. A mark price is a venue-defined valuation used for risk or P&L. These prices can differ, and the contract rules determine which one triggers orders or liquidation.

Evidence: [Create a new order](https://docs.cdp.coinbase.com/api-reference/exchange-api/rest-api/orders/create-new-order); [Oracle prices on dYdX Chain](https://help.dydx.trade/en/articles/166990-oracle-prices-on-dydx-chain); [Mark Prices](https://support.deribit.com/api/v2/help_center/en-us/articles/25944746962973.json)

Canonical: https://degreesofsatoshi.com/encyclopedia/mark-index-last-price/
Published: 2026-10-02
Substantively modified: 2026-10-02
Independently verified by an automated reviewer: 2026-10-02T19:18:00.092Z
Data current through: 2026-10-02

AI-assisted research and drafting with a separate automated source-verification pass; no external expert or named human review is implied.

## Key facts

- **Last:** An executed trade supplies the last-trade observation. ([Create a new order](https://docs.cdp.coinbase.com/api-reference/exchange-api/rest-api/orders/create-new-order))
- **Oracle:** dYdX uses its oracle for collateral valuation and liquidation checks. ([Oracle prices on dYdX Chain](https://help.dydx.trade/en/articles/166990-oracle-prices-on-dydx-chain))
- **Mark:** Deribit’s mark incorporates market signals and stabilizing rules. ([Mark Prices](https://support.deribit.com/api/v2/help_center/en-us/articles/25944746962973.json))

## Three prices can be valid at once

Imagine a last trade at 102, an external reference at 100 and a smoothed mark at 100.5. They answer different questions: what just traded, what the reference method reports, and how this venue values risk. A trader cannot assume a position will close at 100.5 because that is its mark.

Deribit explicitly warns that smoothing can leave a mark outside the current executable spread during fast moves.

Evidence: [Mark Prices](https://support.deribit.com/api/v2/help_center/en-us/articles/25944746962973.json); [Oracle prices on dYdX Chain](https://help.dydx.trade/en/articles/166990-oracle-prices-on-dydx-chain); [Create a new order](https://docs.cdp.coinbase.com/api-reference/exchange-api/rest-api/orders/create-new-order)

## Match the price to the rule

A chart crossing a stop level does not establish that the order’s trigger reference crossed it. The dYdX help pages describe oracle uses and order-specific trigger safeguards. Record the relevant price series, not just a screenshot of the last-price candle.

Evidence: [Oracle prices on dYdX Chain](https://help.dydx.trade/en/articles/166990-oracle-prices-on-dydx-chain); [Perpetual order types on dYdX Chain](https://help.dydx.trade/en/articles/166981-perpetual-order-types-on-dydx-chain)

## Names do not standardize calculation

A mark can combine order-book depth, premium smoothing and bounds. Dated futures may add term-structure or option-derived inputs. These are the cited venue’s techniques, not a universal formula every decentralized derivatives market follows.

Evidence: [Mark Prices](https://support.deribit.com/api/v2/help_center/en-us/articles/25944746962973.json)

## Questions

### Can I buy at the mark price?

Only if available orders actually execute there. A risk valuation is not itself a standing offer.

Evidence: [Mark Prices](https://support.deribit.com/api/v2/help_center/en-us/articles/25944746962973.json)

## Claims and scope

### mark-index-last-price-quick-answer

Last price is the price of a recent completed trade. An index or oracle price is a reference assembled under a published method. A mark price is a venue-defined valuation used for risk or P&L. These prices can differ, and the contract rules determine which one triggers orders or liquidation.

Scope: {"collection":"defi","dataAsOf":"2026-10-02","blockHeight":null}

### mark-index-last-price-fact-last

Last: An executed trade supplies the last-trade observation.

Scope: {"collection":"defi","dataAsOf":"2026-10-02","blockHeight":null}

### mark-index-last-price-fact-oracle

Oracle: dYdX uses its oracle for collateral valuation and liquidation checks.

Scope: {"collection":"defi","dataAsOf":"2026-10-02","blockHeight":null}

### mark-index-last-price-fact-mark

Mark: Deribit’s mark incorporates market signals and stabilizing rules.

Scope: {"collection":"defi","dataAsOf":"2026-10-02","blockHeight":null}

## Sources

- [Create a new order](https://docs.cdp.coinbase.com/api-reference/exchange-api/rest-api/orders/create-new-order) — Coinbase Exchange. General order policy example; not a claim these policies exist on every DEX. Locator: Time in force; post only; fill or kill. Retrieved: 2026-10-02T19:02:00.071Z.
- [Oracle prices on dYdX Chain](https://help.dydx.trade/en/articles/166990-oracle-prices-on-dydx-chain) — dYdX Operations Services. Source-specific oracle reference and its distinct functions. Locator: Oracle determination; liquidation and trigger uses. Retrieved: 2026-10-02T18:57:09.645Z.
- [Mark Prices](https://support.deribit.com/api/v2/help_center/en-us/articles/25944746962973.json) — Deribit. Official support article retrieved through its public API; venue-specific mechanics. Locator: What is the Mark Price; building blocks. Retrieved: 2026-10-02T19:02:00.584Z.
- [Perpetual order types on dYdX Chain](https://help.dydx.trade/en/articles/166981-perpetual-order-types-on-dydx-chain) — dYdX Operations Services. Order-type semantics and dYdX-specific constraints. Locator: Market; Limit; Stop; Take Profit; execution policies. Retrieved: 2026-10-02T18:53:20.714Z.

## Revision history

- 2026-10-02: First publication after primary-source research and separate automated verification.

## Cite this entry

Degrees of Satoshi editorial project. “Mark, index and last price: different numbers with different jobs.” Published 2026-10-02; updated 2026-10-02. https://degreesofsatoshi.com/encyclopedia/mark-index-last-price/