Combined ratio = average combined ratio for 2014-23 period, weighted by annual GWP
Standard deviation = weighted standard deviation of annual combined ratios reported for 2014-23 period

Criteria for inclusion: 10 years of trading, with more than £100mn of GWP in at least 5 of those years
Also excluded: life syndicates, RITC syndicates and SPAs

* Syndicates which changed ownership/management during the period