Tata Group filed an Expression of Interest for Air India to the Disinvestment Ministry on Monday and will now be expected to submit its financial bid within the next 15 days. This is just an expression of interest and not a financial bid and it has been submitted as the deadline ends today, Tatas told NDTV. An expression of interest indicates a buyer's interest in acquiring a company. The deadline for filing expression of interest ends at 5 pm. It is still not known whether Tatas plan to acquire Air India with their existing partners, i.e. Air Asia or Vistara, or go it alone.