The overround on every market, built from the best price we can find on each runner
across every bookmaker. Under 100% means the whole field can be backed for a
guaranteed return. Below that, the selections where the books disagree most —
which is where value tends to hide even when the full field does not arb.
Read the book gap with care. Sorted by gap alone the top of this table fills
with 50/1-plus shots, and that is not an accident: measured against Betfair's settled
SP over 1,401 runners, the best of our books came in a median 22% below fair,
and at 20/1+ a median half of fair. A big disagreement between books is usually
two books being wrong by different amounts. Beats the exchange is the filter
that tests whether a price is actually generous — only 9.5% of runners pass it.