Maroc Telecom, part-owned by the French telecommunications group Vivendi, is facing increased competition from rivals.
Morocco, with a population of 31.5 million, has three telecoms operators.
Maroc Telecom competes with Méditel, affiliated to France Telecom, and Inwi, which counts Kuwait's Zain among its main shareholders. Inwi started operations in February last year.
By the first quarter of this year, Inwi's market share had grown to 16.7 per cent, while Maroc Telecom's fell below 50 per cent for the first time.
"The way I'm seeing it, Maroc Telecom is becoming the STC of Morocco," said Clement Mauve, an investment analyst at ING Investment Management in Dubai. "The company is facing increased competition on all fronts - fixed line, mobile and internet."
Mr Mauve said he was bearish on the stock.
The operator in July said it no longer expected its revenue to rise this year after lower call prices in its key market cut its profit for the first half. Maroc Telecom reported a 10.3 per cent drop in net income to 3.98 billion Moroccan dirhams for the first six months of the year.
The company has had to cut prices to follow the competition, which was particularly aggressive on mobile phone pricing, Mr Mauve said.
"The main question going forward will be about elasticity," he said. "Especially as prices go down, will Maroc Telecom be able to increase volumes to bring the same level of Ebitda?"
Maroc Telecom shares have been held by hedge fund managers, emerging-markets funds and local fund managers in Morocco because of its traditionally high dividend yields, at 7.5 per cent, but that may change if operating margins go lower, Mr Mauve said.
Morocco has been troubled for months by growing popular demands for political, economic and social reform, after uprisings overthrew leaders in Tunisia, Egypt and Libya.
The company averted a scheduled three-day strike last month by reaching an agreement with unions, as employees demanded higher wages and the introduction of bonuses that reflected increases in the company's profitability.
Maroc Telecom also owns a majority stake in Mauritel, Mauritania's main telecoms company. It also has subsidiaries in Burkina Faso, Gabon and Mali.