FNMAT shares will only reach an equivalent price of about $25. FNMAT themselves will not rise to $25.
The increase in value will be achieved when they the JPS are first converted into legacy commons and then (with a reverse split) into new commons.
This is likely going to happen during a period when all shares are suspended from trading due to recap/release. When you check your account afterwards, there will be no more FNMATs, only new shares (ticker: FNM?).
If the IPO price of FNM is $50, for example, you will find one FNM for every two FNMATs you previously owned.
Tell me though, because I own FNMAT, how do we suddenly see $25? I never really understood that.