I don't understand why you are getting downvoted, because this is indeed what Tether claims. From their homepage "100% Backed Every tether is always backed 1-

I don't understand why you are getting downvoted, because this is indeed what Tether claims. From their homepage "100% Backed Every tether is always backed 1-to-1, by traditional currency held in our reserves. So 1 USD₮ is always equivalent to 1 USD." Whether Tether's claim is actually true is at best unclear, of course.