Dump now and regrets later. Just look at the PE ratio

PE ratio > 56 is a frightening ratio. Only Tech could surpass that. Year on year, we are comparing that with last year EPS. But that is not how you value growth stock, the best way to value this is using Peter Lynch's fair value method by looking at PEG ratio, the limitation, however, is that the EPS growth last year was 185% and this year to be 83% or higher. Sounds too optimistic, but when a company has a niche ability to control cost and a big untouched pie, it is possible that the growth story has years to come.

As a growth stock, A2M is far from overpriced. It's PEG is currently sitting at 0.70. PEG ratio tells a different picture than the PE ratio. It is undervalued.
If Peter Lynch is an Australian or Kiwi, he will get rich with A2M during these small dips. I would love to see it dipping below 10 or even back to 8, but I doubt HC has much power to drive the market force.
With just 5% penetration rate in China IF market and so many other dairy products (butter, yoghurt, custard, cheese, cream) remain untouched, room for growth for a2 depends on the health awareness of consumers, which is still growing. If your counter-argument is the science, you are right with the unknown, the pathophysiology of a1 beta caesin is unknown, the whole concept base on epidemiology findings. But let say it is false science, A2M is like the only grain farmer in the world so far that can produce gluten-free products, what's the matter even if we have a few other farmers that start to produce gluten-free grains? IT JUST MAKES MARKETING MORE EFFECTIVE AT NO EXTRA COST! Simply putm, A2M will be the beneficiary at Nestle expense.
The current market price has not fully realised the true value of Fonterra alliance, another 9b company.
A2M currently have 10B MC but it has the ability to now execute as swiftly as a 19b company under this strategic alliance to fuel further growth, which was previously restrained by the production capacity with the Synlait (SM1) canning facility. In 2018, Synlait new canning facility will start producing, A2M could to exceed the 21cps NZD EPS target this year, which represent an 81% EPS growth. If you look at the chart you would think A2M is rising too quick, surprisingly the company's earnings had outpaced our expectation in the past, there is nothing on the horizon known to us that will slow down the EPS growth just yet, the history of improving operating profit margin minus the marketing cost in US, A2M will only run their company more efficient especially with Fonterra Alliance and increased Synlait production, even if Sales per share slows.
This means that in FY18, we should see a brand with strong pricing power and vertical integration + economy of scale.

Using the Peter Lynch fair valuation method, $17 is fair, upside potential of $20.
Of course, A2M won't grow at this pace forever, the pie is still big and a2 market share is still very small, hence the growth rate is achievable in the short term.
Limitation on using PEG alone is that we do not have 5 years TTM EPS growth for this calculation. So I could be totally wrong on a grand scale.
DYOR. I could be selling in the meantime.