Shares in SCMP Group, which publishes the South China Morning Post, fell as much as 11 per cent during morning trade before recovering in the afternoon. The counter closed 2.36 per cent down at $3.15.

The company then issued a statement saying it was unaware of any reason for the decline, noting that the Hong Kong stock exchange's intention to eventually abolish the newspaper reporting requirement for listed companies had been known since 2000.

'The company has been preparing for this but the actual impact of the change, if implemented, remains to be seen,' the statement said.

An analyst said: 'For listed companies, particularly the large and mid-cap ones comprising most of the advertisers in SCMP, corporate governance, transparency and good investor relations are other considerations for publishing announcements in newspapers.

'The market may have over-reacted to the elimination of print reporting,' he said, adding that many companies would prefer to stick to the traditional method of reporting through newspapers rather than solely on the internet.

Goldman Sachs estimated that corporate notices generated $40 million in revenue for the group, annually. If notice revenue drops 50 per cent after the requirement is abolished, group earnings will fall by an estimated 10 per cent from 2007, it said.

Other local newspapers such as Sing Tao's The Standard and the Hong Kong Economic Times also rely on corporate notices.

'The Standard may be the most affected paper by the new rule as over 70 per cent of its revenue comes from this category,' a market source said.

Sing Tao's shares rose 2.77 per cent to 37 cents.

Corporate notices accounted for about 8 to 10 per cent of revenue at Hong Kong Economic Times, the company said in its listing prospectus.

Its stock price stood firm at $2.15 during yesterday's rout.