H1B Transfer Based on PERM approval

[heyvishy]

Hi,

I am H1B visa and currently in my 8th Year (getting visa extensions so far , based on Approved PERM).

Now, I need to switch to some other employer ( due to some problems with my current employer).
My current Visa expires in Dec 2015, and my current employer has already filed an H1 extension.
So I am assuming my next H1 will be valid till Dec 2016.

My question is ,say i switch to another employer , and they do H1 Transfer.
How long will be my next H1B be valid for ?

Will it be valid only for remaining time in my H1 ?
i.e say my H1 is valid till Dec 2016 and i switch in March 2016. Will the transferred H1B be only valid till Dec 2016 ?

OR

Will it be valid till March 2017 ?

OR

Will it be something else ?


Please advise gurus, as i am really looking to change my employer.
Thank you .