IT companies do inovation in IT not Banks. Banks make large amounts of profit from money people put into the bank. IT companies make money on the volume of IT they sell
It varies from country to country. Every country has a central bank that is the bank for other banks in the country. Ex: Federal reserve system - USA Reserve Bank - India etc
The answer is May be. An investment bank may or may not provide retail banking services like checking accounts, credit cards etc. Their area of expertise is investment services, mutual funds,...