glossary

Market line, defined

Jul 10, 20262 min read

The market line (eo_market) is a single, de-vigged consensus probability for a CS2 match, derived from multiple bookmakers and exchanges.

It is built in three steps. Prices are collected from several sources. Each source is de-vigged independently to remove its margin. The median of the resulting fair probabilities becomes the published line — the median rather than the mean, because one stale or unusually wide source then cannot drag the consensus.

How the market line is served: at least two sources are de-vigged and median-combined into one flat eo_market row per outcome, with book_count as a data field, not a claim.

Two properties are deliberate. The line is published only when at least two distinct sources contribute, so it never reflects a single opinion — though two is a floor, not a promise of depth. Some markets genuinely rest on only a couple of sources, and the data is honest about that rather than implying broad coverage. And no individual source is ever named, and no per-book price is ever served — only the derived aggregate.

Live proof the market line is de-vigged: across 59 open CS2 markets the implied probabilities sum to exactly 100.0000%, with zero individual books named.

What comes back is a market-implied win probability, delivered flat: one row per outcome, each tagged source: eo_market, not a nested structure. A book_count field ships on every row, but it is data for your own use, not a marketing claim. The honest framing of the line stays "a de-vigged aggregate combined from multiple bookmakers and exchanges," never "odds from N books." Across every live market the two sides sum to exactly 100.0000% once de-vigged, which is the whole point: there is nothing left to strip out. Compare it against your own model; don't read it as a recommendation. The approach (aggregate several sources, de-vig, take the median) is a standard way to read a forecast out of betting prices — see Štrumbelj, 2014.

Our own model line, eo_model, is coming soon, once it clears validation.

Read the methodology, or see reading the CS2 market odds line via the API.

The same arithmetic on your own numbers: the free no-vig calculator.