Airline loyalty programmes are cumulatively worth over US$160 billion, with Delta Air Lines’ SkyMiles programme rated the single most valuable in the world, according to a new report from On Point Loyalty.

The estimated value of Delta SkyMiles was set at more than US$21.7 billion based on a set of 50 variables, including metrics on the airline, the loyalty programme, credit-card industry, and local market dynamics, according to the management consulting and capital firm, which focuses on airline loyalty, frequent flyer programmes, and travel technology companies.

American Airlines’ AAdvantage programme was estimated to be worth in excess of US$19.5 billion, followed by United Airlines’ MileagePlus programme (US$16.4 billion), Southwest Airlines’ RapidRewards (US$6.3 billion), and the Flying Blue programme jointly run by the Air France-KLM Group, Kenya Airways, and Tarom (US$6.2 billion).

Rounding out the top 10 loyalty programmes were Miles&More from the Lufthansa Group, LOT Polish, Luxair, Adria Airways, and Croatia Airlines (US$5.7 billion), Avios from British Airways, Iberia, Aer Lingus, Flybe, Vueling, Meridiana, and Comair (US$4.7 billion), Japan Airlines Mileage Bank (US$4 billion), KoreanAir SkyPass (US$3.7 billion), and All Nippon Airways Mileage Club (US$3.6 billion).

Airline loyalty programmes have approximately 288 million active loyalty members, who earn around 3.5 trillion points annually.