I'm sure this has been asked before, I just can find it. I have a loan to purchase a second home that will be secured by both the dwelling being purchased and their current residence (the loan is not a bridge or short term loan). I know that HOEPA does not apply to a purchase transaction, but since we're taking a lien on their existing dwelling, will HOEPA apply, even though this is a residential mortgage transaction?

Yes HOEPA will apply. Your loan may be a purchase transaction but it is not a Residential Mortgage Transaction. See the definition of a RMT at 226.2(24).

I forgot that for it to be a RMT it had to be the principal dwelling. Thanks