Jesus's Name is "God Is Our Righteousness" (Jer 23:6).
When we abide in Him, "God Is Our Righteousness".
The righteousness of faith is defined as "being forgiven" (Ro 4:6-8).
So, people say "That's a negative righteousness, like saying our bank account is at zero, but we need a positive righteousness, too," so they speculate that "Jesus imputed His righteousness to us".
Think about that for moment: if God assesses your life, is He going to congratulate you for things Christ did? "Thank you for going to the Cross and dying for all men"? You will not be told that--nor will anything else He did be addressed to you.
So, what is the "positive righteousness"? If we don't accept His testimony, we call God "liar" (1 Jn 5)--if we do accept His testimony, we call God "true". That is our "positive righteousness"--we have called God "true".
Recall that all unrighteousness suppresses God's truth (Ro 1:18), so if faith in Him is saying He is true, it is revealing His truth in the world, thus it is righteousness. This, too, is an act of God, since it is only His grace that permits it (Ro 2), but it is not "the righteous life of Christ imputed to us", it's an act of God done in our lives together with us.