what is the likely reason that the bank have a different year end than the other companies

Question

what is the likely reason that the bank have a different year end than the other companies

Answer 1

The exact Financial calander followed is different for different regions/countires. The difference is more historical and a convinient practise that has no advantage / reason to change.
Many Countries like US/Japan the Financial year can be choosen by companies and needs to be same every year. This need not be same as the Financial year followed by Government.
Typically Banks would follow the Financial year followed by Government as this would have more direct impact on the business per say in terms of policy changes which are typically from the begining of new financial year for Government. If the Banks follow a different calander, there would be additional overhead of segregating transactions for reporting.
Large corporates on other hand would tend to follow a Calander year as it is more convinient when operating in different geographies.

There is a very good article on wikipedia
http://en.wikipedia.org/wiki/Fiscal_year