The problem is the Singapore domestic legal market is too small and uncompetitive. The US/UK law firms are forced to self-report their data to Amlaw because their competitors are doing it. If they don't, then they just won't be included in the annual Amlaw rankings, which will be a severe hit to their market image (and ego).

Here, however, we only have a handful of big firms and none of them are under any pressure to report data because no one is going to "spoil market" by doing so first.