Vodafone Group plc (NYSE: VOD) has got off to a good start in what could be a pivotal week for the mobile giant, unveiling better than expected subscriber growth in its first quarter. (See Vodafone Reports Q1.)

That's the calm before the storm, though, as Tuesday brings the company's annual shareholders' meeting, where it's expected that some major institutional shareholders will oppose the re-election of CEO Arun Sarin to the operator's board.

Weekend media reports suggest that a number of major shareholders, which between them hold up to 10 percent of Vodafone's stock, are eager to see the back of Sarin, and will seek to undermine his position at the meeting by opposing the proposal to re-elect him to the board.

Discontent has been brewing over Sarin's performance as CEO for some time. Vodafone's share price has been on the slide in the past despite a share buyback scheme and the carrier's decision to return $10.5 billion to shareholders following the sale of its Japanese operation. (See Vodafone Cashes In on Japan and Pressure Mounts on Vodafone CEO.)

In the past year, the carrier's stock has lost more than 20 percent of its value -- dropping from 144 pence a year ago to 115.25 pence today on the London Stock Exchange -- and the company has issued three profit warnings, the most recent in late May, when it announced a massive annual loss due to asset writedowns and its entrance into the fixed broadband market. (See Vodafone Unveils Convergence Plans and Vodafone Rings Warning Bell.)

Today, Vodafone's share price rose by 4 pence, nearly 4 percent, to close at 115.25 pence, giving the carrier a market capitalization of £69.4 billion (US$128 billion).

That fillip came from the key performance indicators (KPIs), which showed net subscriber additions in the three months to June 30 of 4.5 million globally, higher than the expected 4 million. Analysts at Lehman Brothers reckoned the numbers were "better than we expected," though noted in an email issued to investors today that the core European markets of Italy, Germany, and the U.K. had not performed as well as expected.

In addition, Vodafone today announced the resignation of one of its most highly respected executives, Bill Morrow, who has stepped down as CEO of Vodafone Europe to return to California for family reasons.

Ovum Ltd. analyst John Delaney expects Sarin to come under fire on Tuesday. He stated in a research note today that "the markets have yet to be convinced that Vodafone's board has a plausible plan to get the company's top line into sustained double-digit growth over the long term," and that "as a result, the value of shareholdings continues to take a beating."

Delaney reckons today's KPIs "look good enough to let Sarin fend off the attacks for a little while longer," but that the CEO will need to come up with concrete plans to boost revenue growth beyond the expected 5 percent to 6.5 percent for the full year if he is to "keep the shareholders at bay for much longer."

— Ray Le Maistre, International News Editor, Light Reading