"Sumit Bose has got the formal orders to assume charge as Revenue Secretary and R S Gujral too have been informed to work as Expenditure Secretary," a senior official told PTI.
The key change comes within a week of P Chidambaram taking charge as the Finance Minister on August 1.
However, the official added that Gujral being the senior most officer would continue to be the Finance Secretary.
Gujral was part of former Finance Minister Pranab Mukherjee's team which came out with the controversial proposal for introduction of the General Anti Avoidance Rules (GAAR) for taxing overseas transitions.
He was also involved in the budget proposal amend the Income Tax Act with retrospective effect to tax overseas deals involving domestic assets.
The amendment had implication for the Vodafone case under which the British Telecom giant may have to pay Rs 20,000 crore as capital gains tax despite winning the legal battle in Supreme Court.
As regards GAAR, the Prime Minister office had appointed a committee under tax expert Parthasarathi Shome to look into the concerns of foreign and domestic investors.
