what is sponsor bank..?
Basically to sponsor means to allocate fund/resources...
To better understand the term... lets take an example of regional rural bank which is sponsored by three autonomus bodies viz. central govt,state govt, and a nationalised bank(pnb/bob etc).
So the bank that provide fund to the rrb or any finanacial org. for the purpose of lending on their behalf is called Sponsor Bank,whereas the bank receiving the fund is said to be sponsored bank.
Hope I m clear @ Alka