Hong Kong's securities regulator says listed companies should tighten up on how they disclose inside information.

In its latest newsletter, the Securities and Futures Commission (SFC) warned that relying on corporate websites and social media to disseminate news risks uneven disclosure and potentially breaches securities laws.

“Listed companies should strive for accuracy, clarity and balance when making announcements,” said the regulator. “Selective or uneven dissemination of inside information will undermine market integrity.”

The point raised by the SFC made headlines in April last year when Twitter’s own financial results were released nearly two hours ahead of schedule by a data mining company.

SFC noted instances of its own market reacting to information posted by a company’s senior management on social media.

On one occasion, a director of a retail company talked about the full-year sales target through his personal social media account.

The expected sales growth figure he gave was a significant drop compared with the sales growth of the previous year. The share price of the company fell significantly shortly after the post.

Shareholders who didn't follow the director on social media were less likely to be aware of the company’s negative outlook.

“They were denied the chance to take this information into account when considering their investment decisions,” said the regulator.

“Clearly this event raises a number of issues that should be considered by listed companies.”