Hi
See following link.
http://www.ukba.homeoffice.gov.uk/si...ntspolicy1.pdf
48. The family member of the Tier 2 Migrant must have £533 to support himself/herself.
49. This requirement can be met by:
• having savings of £533 which must have been held for at least three months prior to the date of application; or
• the Tier 2 A-rated sponsor providing a written undertaking that, should it become necessary, it will maintain and accommodate the family member for a month. The undertaking may be limited provided the limit is at least £533 per family member.
If your employer is A rated sponsor and has ticked maintainance option in Sponsor Management Sytem while issuing Certificate of sponsorship, then Letter from your sponsor is sufficient.
If he is not ticked the maintainance option, then you need to maintain 800(you)+533 (your wife) = 1333 GBP in your UK bank acccount or Equivalent Indian Rupees in your Indian Bank account.
Check your Certificate of sponsorship(COS) again.
Thanks
Som