New Delhi, May 23: Shares of oil companies tumbled up to 8 per cent today on worries that the government may ask them to share the burden of higher petrol and diesel prices.

Hindustan Petroleum Corporation plunged 8.06 per cent, Bharat Petroleum Corporation 6 per cent and Indian Oil Corporation slipped 4.89 per cent on BSE.

Shares of Oil & Natural Gas Corporation (ONGC) also fell by 4.75 per cent.

There was a 19-day freeze in revising rates before Karnataka went to polls, and since the time hiatus ended on May 14, rates have gone up by Rs 2.54 a litre in case of petrol and Rs 2.41 in diesel.

The BJP-led government had in June last year junked a 15-year old practice of revising rates every fortnight and introduced daily revisions, which worked well except periods immediately preceding an election. Meanwhile, state-owned HPCL today reported 4 per cent drop in its March quarter net profit on lower refining margins and inventory gains.