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Every Belief Index level is the output of a fixed production pipeline: define a theme, screen the eligible markets, weight the basket by published rules, value it at regular valuation windows, and publish a chain-linked index level. This page walks through that pipeline end to end. Each stage links to the full methodology document that governs it.
If you are familiar with how equity index providers operate – a published rulebook, an eligible universe, systematic weighting, scheduled rebalances – the Belief Index pipeline will feel familiar. The differences are the underlying instruments (prediction market contracts rather than equities), the valuation cadence (every 30 minutes rather than end-of-day), and the fact that every input is public: the order books the levels are computed from, and the venue settlement records resolutions are confirmed against, are open to anyone who wants to check the arithmetic.

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The Production Pipeline

1

Define the theme

Each series begins with a coherent question – “how is the market pricing the 2026 easing cycle?” – and a universe of prediction markets that bear on it. Themes are chosen so the index level reads as an answer to one category-level question.
2

Screen for eligibility

Candidate markets pass published screens: minimum liquidity and order book depth, resolution clarity (an unambiguous settlement source), thematic relevance, and duplication checks. The criteria and thresholds are documented in Market Selection & Weighting.
3

Weight the basket

Constituent weights follow the published formula, with concentration caps so no single event dominates the series. Weighting is systematic – the same inputs always produce the same weights.
4

Value at valuation windows

At each valuation window – currently every 30 minutes, subject to change – every constituent is priced from its observable order book midprice. If a fresh price cannot be fetched, the system falls back to the last known good price and flags the computation as stale – the flag is published with the level, never hidden. The full computation is specified in Index Calculation Methodology.
5

Compute the index level

The basket valuation (the raw index value) is rebased so each series starts at an index level of 100 at inception and moves proportionally with the underlying basket. This is the published, citable number.
6

Handle resolutions

When a constituent market resolves, its settlement value ($1 or $0) folds into the level – the discrete, binary event is absorbed by the rest of the basket. Fixed-term series run until all constituents resolve; in Perpetual Series, from 2026-09-30, a resolved market keeps its settlement value until the next scheduled review, where it leaves the basket and the remaining weights are scaled up in proportion (a review that also adds markets re-weights the composition).
7

Reconstitute with chain-linking

When a Perpetual series changes composition, the old and new baskets are chain-linked at the reconstitution point – the standard index technique that ensures composition changes never create artificial jumps in the published series. Every reconstitution leaves a full audit trail.

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Valuation Windows: The Heartbeat of the System

Valuation windows are the periodic checkpoints at which every series is revalued and its index level published. Think of them as an index provider’s calculation schedule – but running every 30 minutes rather than once at the close.
Index levels are theoretical values computed from midprices, not execution prices. They assume constituent positions could be valued at the mid of each order book, without spread, slippage, or market impact. This is the standard caveat for any published index – and it matters more here because prediction market order books can be thin. See Risk Factors for the full discussion of theoretical-versus-executable limitations.

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What Moves an Index Level

The underlying prediction markets move as new information arrives – polling data, economic releases, policy announcements, and other catalysts shift the implied probabilities of event outcomes. Each valuation window reprices all constituents using the latest order book data.For example, if a strong jobs report suddenly prices down the probability of rate cuts, all rate-related constituents in a rates series adjust – and the index level reflects those movements at the next window.
When an event resolves, the constituent settles to $1 (if the tracked outcome occurred) or $0 (if it did not). This is immediately reflected in the level.Resolution events are the defining feature of event markets: they create discrete, binary value changes. A diversified basket absorbs these events across multiple constituents, which is what turns binary settlement noise into a continuous, readable series.
On a scheduled review cadence, Perpetual series retire resolved or ineligible constituents and admit new ones under the published criteria. A resolved constituent leaves only once its venue’s final settlement record reports the outcome; a market the venue has closed but not yet settled stays a constituent until then. Chain-linking ensures the level is continuous across the change: the index measures the theme, not the turnover. See Perpetual Series.
Index levels are computed gross of fees, spreads, and slippage, exactly as an equity index is. They are theoretical measurements of a basket, not the return any holder of that basket would have realized.

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Data Integrity Controls

The same production system that computes index levels enforces a set of integrity controls, all designed to prevent a bad number from ever being published: The system prioritizes integrity of the published data over continuous availability.

Index Calculation Methodology

The full computation, step by step – replicable with a spreadsheet.

Market Selection & Weighting

The eligibility screens and weighting formula.

Worked Examples

Full numerical examples of every computation.

Perpetual Series

Reconstitution, chain-linking, and review cadence.