In this post, I will shed some light on how airlines assign fare basis codes to the various “buckets” of inventory available for sale on any given flight. If you’ve ever wondered what pricing “buckets” are, or just what your fare showing as WAGT14GS means, read on. My recent Mileage Run 101 posts (Part 1 and Part 2) got me to thinking about demystifying these rather unfriendly looking codes, and I draw upon my experience working in Inventory Management (IM) at United Airlines, as well as my personal fascination with codes and logic in general, for this tutorial. The middle “Fare Class” column below, as shown using the FlyerTalk tool of FareCompare, is what I’m referring to [Edited to add: Since this post was published, FareCompare took down the FlyerTalk tool, sadly]:
Since I’m most familiar with United’s fare basis structure, and some of the logic & sequencing hasn’t changed in decades for domestic fares, I’ll discuss those here. Keep in mind for now that other airlines have slight variations to their coding logic. To start, it’s important to first look at that leading letter of the “fare class.” The second line of the chart above shows a fare basis of GA14CS as the fare class for the $160 base price from Los Angeles to Nashville. G, then, is the “bucket” this fare falls into, a way the airlines categorize fares based on their yield potential. (That first fare to St. Thomas is out of scope for purely “domestic” fares, but I plan to decode international and other outliers in the future.)
There are presently almost two dozen revenue buckets at United, namely F & A (first class); J, C, D & Z (business class); and Y, B, E, M, U, H, Q, V, W, T, S, K, L & G (economy/coach class). Each represents a level of revenue contribution to the carrier, and all fare bases are not created equal. Basically meaning that you can’t arbitrarily assume the fare and/or yield of a ‘S’ fare, for example, carries the same weight across all routes.
Within each bucket, there exists a range of contribution levels depending on the origin & destination (O&D) of the ticket purchased. This simply means that a ‘S’ fare might generate a better yield to the airline if flown on a ticket purchased from Seattle to Chicago to Atlanta, versus a ‘S’ fare flown from just Chicago to Atlanta. Since the airline wants to maximize the higher earning buckets and overall yield, they may restrict S-class from being sold on that Chicago to Atlanta flight, but offer it on the Seattle to Chicago to Atlanta connection combination. For an excellent summary of this “married segment” concept, take a look at this current article by Ben Schlappig, an indefatigable mileage runner well beyond his years.
Now here’s where the airline yield management systems really come into play. Those systems, such as the one I worked with during my tenure in Inventory Management (IM) at United in the 1990s, optimize literally more than one hundred combinations of buckets across every O&D market to determine how many seats to allocate within each range and bucket. This process is constantly running in the background, but analysts in IM do go in to make adjustments, as I did for my assigned markets.
How to determine the amount of seats to authorize within each input area is highly proprietary, but the basics include using historical flight data, seasonality, market demand, and competitive considerations. So, the reason the lowest fares you’re searching for may already be sold out is because the airline thinks they’ll be able to sell those seats at a higher value & will assign them accordingly.
Okay, back to fare bases. Now that you know about buckets and why there are so many of them, let’s look again at the rest of the alphanumeric characters following that leading identifier. The second letter usually determines if it’s a one-way or roundtrip fare. Without exception, an ‘A’ domestic fare on United means it’s one-way, and an ‘E’ means roundtrip (excursion). Mileage runners like myself aim for those one-way fares since we know there aren’t any minimum stay requirements and can then turn right around and continue flying without a stopover. Using that L.A. to Nashville fare basis again (GA14CS), we know it’s a one-way fare since the second letter is an ‘A.’ Great, let’s move on.
Most of the time, the numbers contained within the sequence refer to the advance purchase requirement of the fare. Using the Nashville example again, GA14CS, the 14 here represents the advance purchase (AP) required to qualify for that fare. Pretty simple. However, there may be some other fare bases out there with more numbers.
For example, there was a fare out there yesterday from Los Angeles to Newark showing a fare basis of WEG143GS. We know it’s assigned to the W bucket, but what does the 143 mean? In this case by reading the fare rules (via ITA Software or ExpertFlyer), you’ll see the fare does have a 14-day AP, but also has a minimum stay requirement, generally requiring a three-night stay, hence the ‘3‘ attached directly to the end of ‘14.’ You can easily break out what might be the advance purchase by knowing the most frequent ones are 7, 14, and 21 days. I’ve also seen 0, 3 & 10-day APs out there, too, as of late.
The next letter in the Nashville fare (GA14CS), for example, is a C. Most of the time, but not always, it represents an internal pricing strategy the revenue management (RM) department wants to assign to the fare, and generally has no correlation to an element of the fare rule. But like I say, that’s not always the case, but I’ll come back to that after I shed some light on that last letter of ‘S.’
Also without exception and unchanged for years at United, if a ‘S’ or ‘N’ follows anywhere after the advance purchase & minimum stay numbers for a domestic fare, it means the fare is non-refundable. It is commonly the last character in the string, but may not be always, as in the case of the Los Angeles to Augusta fare of LA21N6K appearing in the list above. It’s my assumption that the -6K is also a unique RM identifier not correlating to a specific fare rule element.
So, we now know the GA14CS L.A. to Nashville fare is a one-way (‘A’), non refundable (‘S’) fare in the ‘G’ bucket requiring a 14-day advance purchase (14), while ignoring the ‘C‘ for our consumer-centric purposes. What about that WEG143GS fare from L.A. to Newark I mentioned above? We know it’s a roundtrip (‘E’), 14-day advance (14) fare with a minimum stay of 3 nights (3), is nonrefundable (‘S’) and the second ‘G’ is unimportant to us, but what about that first G?
Reading the fare rules, we know (via my IM experience) that ‘G‘ denotes the fare is valid only on nonstop flights. Sometimes United will use that same letter, or perhaps a two character combo, but I guarantee there is something specific in the fare rules that letter refers to. And it will always appear before the numeric portion of the fare basis. Another similar fare basis was out there yesterday from L.A. to New York (all airports) of WAG14GS. Again, this fare is valid on nonstop flights only as denoted by the G.
As you can see, there actually is logic to the rather cryptographic looking fare basis codes, and each airline has their own practice with which to assign codes. American has a totally different combo of letters and numbers, but with a little research into the rules, you’d be able to figure out a general sequencing as I’ve done above for United.
I actually have one more nuance to reveal. Assuming the fare stays live here for the next couple of days & the fare rules don’t change, I’m referring to the L.A. to Washington DC (all airports) fare basis of WAGT14GS with a base of $296. Anyone want to take a guess and decipher the ‘T’? Hint: The answer definitely lies within the fare rules, and it’s not simply a two character way of denoting the fare is valid on nonstops only. I’d enjoy it if one of my few readers commented with their answer, but if no one does, I’ll post the answer in a comment during the next couple of days.