Originally Posted by
normcpa
AA.com prices A-B and B-C (separately) with P inventory on both flights as expected. AA.com prices A-C with a connection in B (identical flights) with P on A-B and A on B-C (~$200 higher fare).
That's probably due to a so-called "married connection". Most airlines nowadays use dynamic inventory tailored to the origin and the destination of the whole trip. If their yield management system predicts that flights from A to C can be sold for a higher price this is what you experience. Annoying, but normal.
One has to add that this does not necessarily have to work against you. Quite often, married connections yield to lower fare classes opening up when flying from A to C compared to city pairs A-B and B-C.