Valeant under investigation by US regulators

Valeant Pharmaceuticals is being investigated by the Securities and Exchange Commission, it has confirmed.

"The company confirmed that it received a subpoena from the SEC in the fourth quarter of 2015," said Valeant spokeswoman Laurie Little.

Valeant, which has been struggling to maintain investor confidence amid mounting scandals, said the SEC probe was one of "several ongoing investigations".

The firm's shares closed down 18%.

The statement comes a day after the company announced, external the return of its chief executive J. Michael Pearson from medical leave.

It also said it would postpone the release of its fourth quarter earnings and scrap its previous financial forecast.

The company also cancelled a planned call with investors.

The investigation is separate from one involving the purchase of Salix Pharmaceuticals that was made public last year.

Ms Little said: "Valeant confirms that it has several ongoing investigations, including investigations by the US Attorney's Offices for Massachusetts and the Southern District of New York, the SEC, and Congress."

The US Securities and Exchange Commission (SEC) is separately already investigating whether Salix Pharmaceuticals - which Valeant purchased in 2015 - misled investors about its inventory levels in 2014.

Valeant is also under scrutiny for its connection to speciality pharmacy chain Philidor RX Services. Valeant cut ties with the pharmacy in October, after it was accused of using the pharmacy to falsify sales to boost prices.