There's typically a seasonal jump in the stock of SodaStream (SODA) - Get Report , as investors anticipate that consumers will grab up the company's home carbonation systems as holiday gifts.

This year's spike, though, has been above and beyond - in fact, way above and beyond - the bulge that some previous seasons have experienced. It's a move that seems to suggest that the valuation of the consumer appliance maker has gone beyond the fundamentals the company can sustain, and that, at its current price, a lot of good news is baked into the stock. If that's the case, as the stock strains to break through the $40 barrier, the remaining upside in a stock may be limited.

Four of the five analysts that cover the company have what amounts to a "hold" rating on the stock; the fifth rating is a "sell." The coverage comes from Roth Capital, which has a "neutral" rating, and a $33 price target, and had cut its rating on the stock in August, before the latest uptick in the stock got underway. Jefferies has a "hold" rating, while Susquehana Financial and J.P. Morgan have "neutral" ratings. There are no "buys" on the stock. None of the analysts has a price target of more than $39 a share, and most are considerably lower, even though almost all of those analysts have reevaluated the stock since the last earnings report by the company.

To be sure, there's some good reasons SodaStream stock has surged 60% in little more than a month, moving from $25 a share Nov. 4 to its current high of $39.86 in Thursday's intraday trading. On Nov. 10, the home appliance maker reported fiscal third quarter earnings of 69 cents a share. That beat estimates of 24 cents by 187%.

And that for the quarter ended Sept. 30, meaning that it didn't include the sales of units intended to be gift-wrapped and stashed under the tree.

It's a testament to SodaStream's adroit execution of a nifty repositioning. The Israeli company, which came public in 2010, initially billed itself as a soda maker, a rival really to Coca-Cola (KO) - Get Report and Pepsico (PEP) - Get Report , only without the cost and waste of the bottles.

It worked until it didn't. In much the way consumer appetites for the sweetened soft drinks of big beverage makers have eased, SodaStream appliance owners soured on adding flavor capsules to their carbonated water. SodaStream stock crashed, and badly: from a June 2011 high of $75, the stock traded below $12 this past summer.

So SodaStream did the pivot. Instead of merchandising an appliance that made cola, it billed itself as a sparkling water machine. It told its customers: "Love your water." Sure, it no longer enjoyed the profit stream of the flavor capsules. But it still sold the appliance: in the September ending third quarter it moved 788,000 units, a 23% increase. And sales of its CO2 cartridges carbonated 350 million liters of water. It's practically a healthy product merchant.

And thereby the persistent rub with SodaStream. Just how does it market itself? On value? Frankly, factoring in the cost of the appliance, and the CO2 cartridges, consumers could do as well purchasing private label sparkling water brands. Convenience? You have to go to the store to buy those CO2 cartridges. Health? Sparkling water is sparkling water, whether you carbonate it yourself or you buy it premade. On environmental issues - a big focus of its somewhat controversial marketing campaigns - it probably wins: "stop clogging landfills with empty plastic bottles" is a compelling message.

Fundamentals like marketing aside, there's the question of valuation. With its recent ascent, the forward P/E has grown to 25 times, a 41% move in the span of a month. Meanwhile, revenues for the current quarter are expected to increase just 10%, a rather modest showing for a stock with that ripe a P/E. (Granted, there's every chance SodaStream will blow through the sales expectations.)

So as SodaStream stock strains to top $40 - a threshold it hasn't traded at since May 2014 - investors have to wonder that, even with a happy holiday season for the appliance maker, there won't be a January hangover.