The opaque practice of fee bundling has been standard practice amongst custodians for decades. The term best execution is used generically when pitching clients to win transition management business. However the unsavory reality is that undisclosed markups in currency transactions are used to compensate transition service providers without consulting fiduciaries.
Plan sponsors are demanding more transparency from transition managers which is a positive development. Proper independent oversight (FX TCA) is essential to ensure the promises of best execution are realized.
For more on the topic:
http://www.pionline.com/article/20130624/PRINTSUB/306249992/exits-change-transition-management-landscape