Yes and No. From my experience they do include W2s in your mortgage application in order to see your total assets in case you go bankrupt. They get as much info

Yes and No. From my experience they do include W2s in your mortgage application in order to see your total assets in case you go bankrupt. They get as much info as they can, which is why they need your w2s ;) The rule for mortgage applications is still based on your monthly gross income. In the background, the actual decision is made off of your gross monthly income/debt ration. Otherwise if your employer's stock crashes tomorrow or if your annual performance is crap, they're pretty much screwed. Trust me they don't take any risks anymore since 2008. It's just as you said "a security", it doesn't impact the approval of your mortgage application.