If we originate 100 HELOCS in the previous 2 years (2017, 2018), we have to report in 2019?
What if we originate 50 HELOCs in 2017 that point, I know I won't be HMDA reportable in 2019 even if we originate 100 or more 2018.
Do I still collect the GMI information in 2017? in 2018?
No and No - for HMDA. If the HELOC's are subject to Reg B's §1002.13(a) (purchase/refinance principal dwelling), then you would collect GMI for that purpose, but not report it on your LAR as your not subject to HMDA.
Or do I just have to collect GMI information on my HELOCs regardless of we end up reporting or not?
No. Over collection of GMI is a violation of Reg B.
IF you became subject to HMDA in later years, you then start collecting GMI (it will be called "Demographic Information" in 2018) on applications RECEIVED in that year. IOW, you don't need to collect GMI on an application now because you might be subject to HMDA next year.