Apple (NASDAQ: AAPL) investors may already be on edge as of late, with the company's stock down about 20% from a year ago, and profit down over $2 billion this past quarter, year over year. Although Apple recently announced share repurchases, and boosted its dividend by 15%, many Apple stock investors aren't satisfied.

To top it all off, the latest numbers from Canalys show that Apple's arch rival, Samsung, shipped 82.2 million smart devices in Q1 2013, taking up 26.6% of the worldwide smart device market, while Apple took 19.3%. Surprisingly, Microsoft (NASDAQ: MSFT) took the No. 3 spot with 18.1%, mainly becuase Canalys considers smart devices to be smartphones, tablets, and notebooks.

The numbers aren't exactly detrimental to Apple, but they should still concern investors. For a while, Apple held tablet and smartphone dominance, but its grip is starting to wane.

On the tablet front, Apple has lost some of it luster, but still maintains a 46.4% market share. The problem is that the iPad lost ground to Android units for the third consecutive quarter, even while Apple's tablet sales have increased 65% from its previous quarter. The iPad Mini is driving the increased sales, but with the product already firmly in the market, its hard to imagine where Apple is going to make significant gains in tablet market share in the near future. The Mini's $329 price allows other companies to severely undercut Apple in price, and gobble up more market share.

In the all-important smartphone segment, Samsung managed to grow its unit volumes by 64.3% compared to Apple's 6.7% growth – Apple's smallest smartphone shipment growth since the original iPhone launch. All of this increased Samsung's smartphone market share to 32%, leaving Apple with about 17%. Yes, Apple shipped 37 million iPhones in the quarter, but declining market share isn't something to be ignored. 

Over the past few years Apple has experienced a huge increase in premium smartphone competition, and with the recent Galaxy S4 launch, Samsung has shown no signs of easing the pressure. 

What Apple needs
Apple is obviously still an extremely important player in mobile, and it's not even close to being pushed out of the smartphone and tablet space. But these latest numbers show that global consumers have warmed to other device makers, and Android's iron grip is getting stronger – with the OS accounting for 59.5% of all smart devices shipped.

The combination of Samsung's increase in shipments outpacing Apple's, along with Apple's falling margins and mobile market share, isn't welcoming news for investors. For Apple to reverse the trend, it's going to need a major change with the iPhone ­– meaning an overhaul and a cheaper version – so it can win back some its lost market share. The tablet market won't be as easy to gain ground in, unless Apple decides to lower the price of the iPad Mini and squeeze out some of the competition. It's certainly not out of the realm of possibility, but with the Mini's lower margins, it's not a move that Apple would take lightly.

With smart devices all around us, it's incredible to think just how much of our digital and technological lives are almost entirely shaped and molded by just a handful of companies. Find out "Who Will Win the War Between the 5 Biggest Tech Stocks?" in The Motley Fool's latest free report, which details the knock-down, drag-out battle being waged by the five kings of tech. Click here to keep reading.

Fool contributor Chris Neiger has no position in any stocks mentioned. The Motley Fool recommends Apple. The Motley Fool owns shares of Apple and Microsoft. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.