The operator is now licensed for 3.8 million passengers, an increase of around 800,000 in the last six months and a leap from the 2.94 milllion it was licensed for 12 months ago.
The number two operator is now well clear of rival Thomas Cook, whose main Atol now accounts for 2.47 million passengers, an increase of less than 82,000 in the last year.
The Atol top 10 gives an indication of which companies are expanding and are an indication of their plans for the year ahead.
Tui UK remains top of the league, licensed for 5.68 million, compared with 5.39 million a year ago.
The September renewals also show direct-sell British Airways Holidays expanding. It is now licensed for 940,000 passengers, compared with 786,000 a year ago.
Also making the top 10 September renewals are Expedia, Travel Republic, Southall Travel and Trailfinders.