We've just recently passed Nokia (NYSE:NOK) CEO Stephen Elop's two-year anniversary of taking the reigns at the struggling Finnish smartphone maker. He was named CEO in September 2010, leaving his position as president of Microsoft's (NASDAQ:MSFT) lucrative business division.

He was tasked with the mother of all turnarounds, after Nokia had fallen on hard times in the face of merciless competition from Apple's (NASDAQ:AAPL) iPhone and Google's (NASDAQ:GOOGL) Android OS. Two years in, how's he doing?

Not so good
The turnaround Elop envisioned was hinged upon the success of his former employer and its Windows Phone platform. Just six months after becoming CEO, he sent out a brutally honest memo to the troops, likening the company's current strategy to "standing on a burning platform." Exactly two days later, Microsoft and Nokia would announce a broad partnership whereby Nokia would adopt Windows Phone as its primary platform.

The rest, as they say, is history. Just take a look at how trailing-12-month smartphone unit sales have looked ever since.

Source: Nokia.

Trailing-12-month smartphone unit sales peaked shortly after Elop became CEO and have subsequently fallen by nearly half since, as it ditched Symbian and Meego. Quarterly smartphone revenue doesn't look much better.

Source: Nokia.

Even when Nokia unveiled its new flagship Lumia 920 Windows Phone 8 device, shares quickly plunged by as much as 15% as investors expressed a certain lack of confidence in the device's ability to compete meaningfully against the then-unannounced iPhone 5 and worthy Android competitors. Microsoft would then go on to hook up with former flame HTC, announcing a new Windows Phone 8 flagship of its own that even bears a noticeable resemblance to the Lumia 920.

Samsung also recently dethroned Nokia as the world's top-selling mobile device vendor by units, after Nokia reigned for 14 years. This turnaround isn't working out as well, or as quickly, as Elop had hoped. Surely investors are getting impatient by now. How long before they give Elop the boot?

Not so long
According to a recent Reuters report, Elop's time may be running thin. Some analysts and investors think Elop only has a matter of months to justify the all-in bet on Windows Phone, saying that early 2013 will witness his moment of reckoning.

One analyst, Magnus Rehle, was quoted as saying that Elop has had sufficient time after two years, but now "time is up." Institutional investor Juha Varis, whose equity fund holds Nokia shares, has given up on the holiday season, hoping that Nokia will have a better shot in the spring: " The beginning of next year may be the final judgment. I think that maybe the end of the first quarter is the marking point."

Nordea analyst Sami Sarkamies gives Elop credit for taking a big risk that could have paid off, something that Nokia desperately needed. He played it as best he could, but he simply got dealt a weak hand. Sarkamies also thinks Elop's clock will run out by the second quarter of 2013 at the latest if he can't prove himself.

Not enough
Nokia's network business isn't doing as badly, falling "only" 8% last quarter, but that's not enough to save the company if its core mobile device segment keeps putting up 26% revenue declines. The location and commerce division is the only one that's growing, but even still we're talking about a modest 4% for a tiny segment.

What was Nokia's chairman Risto Siilasmaa was saying about a "contingency plan?"