New Delhi: The proposed retrospective changes in the income tax law that seeks to bring overseas transactions involving Indian assets into the tax net is likely to yield around Rs.40,000 crore ($9 billion) to the exchequer, Minister of State for Finance S.S. Palanimanickam said on Tuesday.

"The Income Tax department has made an estimation that the total tax implication in consequences of retrospective amendments introduced in Finance Bill 2012 may be to the tune of Rs.35,000-40,000 crore," Palanimanickam said in written reply in the Rajya Sabha.

 However, the minister said it was just an estimate and the exact amount would be determined only when the assessing officer completed assessment proceedings.

 In the 2012-13 budget last month, Finance Minister Pranab Mukherjee proposed to amend the Income Tax Act, 1961 retrospectively to allow authorities to tax global merger and acquisition transactions involving Indian assets and shares.

The proposed amendment is seen as a tool to bring under tax net the overseas transactions like the Vodafone-Hutchison deal.

 The Supreme Court had earlier rejected the IT department's Rs.11,000 crore ($2.2 billion) tax demand on $11 billion Vodafone-Hutchison deal saying Indian tax authorities do not have jurisdiction over overseas transactions.