This is a tricky issue. Initial prequal requests are not applications for HMDA or Reg B, so collecting GMI is technically prohibited. But denied prequals are considered applications for Reg B, meaning GMI is then required (for Reg B, not HMDA). The dilemma is whether it is better to collect the GMI upfront with the initial prequal request (technically violating Reg B if the customer never identifies a property) or to only collect GMI if/when the prequal is denied.
From the Commentary to §1002.2(f):
3.
When an inquiry or prequalification request becomes an application. A creditor is encouraged to provide consumers with information about loan terms. However, if in giving information to the consumer the creditor also evaluates information about the consumer,
decides to decline the request, and communicates this to the consumer,
the creditor has treated the inquiry or prequalification request as an application and must then comply with the notification requirements under §1002.9. Whether the inquiry or prequalification request becomes an application depends on how the creditor responds to the consumer, not on what the consumer says or asks.
Here's another thread on this issue:
https://www.BankersOnline.com/forum/ubbthreads.php/topics/1848966/Re:_Declination_of_prequalific