Let me look into my crystal ball with our current administration...I need some glass cleaner...it's very foggy. If you can figure this calculation out...YOU'RE HIRED! Honestly, you're causing more stress than you need. Today's index is around .40. Add that with a common margin of 2.25% and you'll get 2.65% or 2% lower than what you're currently at (sorry to end with a preposition). FHA - you'll drop max 1%. You may also go up 2%, 5%, or 1% depending on the type of ARM you have. You said Treasury, not Libor, so, if the latter, you should be okay. I don't trust the Fed. Here, I spell it out for you: GOVERNMENT. Your next question should be "How long will I keep this house?" or At what point will I want to refinance? When the rates are higher than they are now or play the Russian Roullette (I can't spell foreign words) game? You need to think about refinancing into another ARM or fix it. Best thing about playing the game is that now is the time to really hammer at the principle of the loan while the rate is low.