Kickbacks, plain and simple. For example: My firm requires we use a corp booking engine. That engine charges a fee to book a ticket online or over the phone.

Kickbacks, plain and simple. For example: My firm requires we use a corp booking engine. That engine charges a fee to book a ticket online or over the phone. We get a slight discount on fares and they in turn give a kickback each year to my employer. The real kicker is that they sell some fares as "refundable" when in reality the fares are just regular fares but allow rebooking via this corporate travel agent. They've essentially locked you into using them and any interaction with an agent incurs a fee. My firm doesn't care, they just see that kickback at the end of the year and are happy. They don't care how inconvenient it is to use the TA. I get some of the desires to control costs but in my case, I have schedules to keep and a lot of last minute travel and the corporate TA is nothing but an inconvenience. I frequently have to put in reasons for "breaking" policy (for example, I don't take red-eyes) on price because the limit between the lowest fare and your ticket is $100. So if the schedule is right but the fare for that is $110, you have to put in a reason why you booked it.