If two friends purchase a home together (file separately) what is the mortgage interest deduction limit? $750,000 per person or $375,000 per person?

[KristinaK]

It depends on each of your filing statuses. If your filing status is either married filing jointly, single, or head of household, then the limit is $750,000. If married filing separately, then $375,000. 

See Pub. 936. 

[Mike9241]

if you are not married the limit is $750K each. However certain states recognize common-law marriages. all states recognize validly contracted out-of-state common law marriages. if a valid common-law marriage the limit is $375,000 each.