Banking Reserves?

Question

How can a bank raise its reserves (internally)?

What effects would attempting to raise reserves have on the banking system and monetary system?

Answer 1

A bank can raise their internal reserves simply by loaning out a smaller percentage of total deposits.

Provided that the bank is large enough, it would shrink the money supply in circulation (since more is kept at the bank) and would raise interest rates (same demand for loans, but smaller supply of money).

Answer 2

It constricts money supply

Answer 3

keep more in its vault