Singtel said it regularly conducts strategic reviews of its portfolio including Optus to optimise the value of its assets, with Optus remaining “a strategic and integral part” of the company, according to a statement Wednesday.

The stock fell by its most in nearly five months after The Australian reported that talks to sell a stake in Optus failed.

Singtel and private equity firm Brookfield had engaged in discussions for a 20% share in Optus, Australia’s second-largest carrier, but couldn’t agree to terms, including price, the report said.

Shares of the Singaporean telecommunications provider fell as much as 4.3% on Wednesday, before the company requested a trading halt.

They’d risen in March when another report suggested Brookfield was looking to buy the mobile network at a valuation of close to US$11 billion.

Optus is one of Singtel’s biggest overseas investments, though its recent history has been marred by a widespread outage that forced the resignation of its chief executive officer in November, following an earlier cyberattack that exposed the personal information of millions of customers.

The Australian carrier’s revenue slid 5.4% in the December quarter while earnings before interest, taxes, depreciation and amortisation fell 1.8%, according to Singtel filings.