BJP had appointed the task force on unravelling the amount of black money stashed by Indians in foreign banks and ways to bring it back.
The report had alleged that Sonia Gandhi and former Prime Minister Rajiv Gandhi were among Indians who held Swiss bank accounts.
This had led Sonia Gandhi to write a letter to Advani denying the allegation.
Sources said in the letter, Gandhi had said that neither she nor her husband held Swiss bank accounts.
This is what Mr Advani wrote to Mrs Gandhi:
Dear Smt. Sonia ji,
On my return from Kolkatta last night I found your letter dated 15 February awaiting me.
I am happy that you have categorically denied the reports alluded to in the Task Force’s report on Black Money. If these had been denied earlier, I am sure the Task Force would have factored in, the denial in its report. Even so, I deeply regret the distress caused to you.