I.S.Tiwana, J.

1. The petitioner-firm, which, though is a registered firm, has been assessed as an unregistered firm for the assessment year 1971-72, by the Income-tax Officer (ITO) for the reason that it failed to file the prescribed Form No. 12 within the time prescribed under Section 139 of the I.T. Act (for short "the Act"). The explanation of the firm for this delayed filing of the declaration on account of its lack of knowledge about the amendment of prov. (ii) to Section 184(7) of the Act with effect from April 1, 1971, was not accepted as bona fide. On an appeal against this order of the ITO before the Appellate Assistant Commissioner (AAC), the conclusion recorded by ITO was affirmed. However, on further appeal, before the Income-tax Appellate Tribunal, the Tribunal disagreed with the abovenoted conclusions of the lower authorities and concluded the matter thus in favour of the assessee :

"So far as the question of existence of sufficient cause for the delay under consideration is concerned, we do not agree with the Appellate Assistant Commissioner that the fact of declaration having been signed on 3-9-1971, was determinative of the assessees knowledge of the chang