Imagine if I bought "stock" in your job. I monitored your performance and set expectations for your work. You fail to meet those expectations, so as the majority shareholder of your job, I have you fired and replaced with someone else. Or you underperform once and I use this threat every single review.

That's how Wall Street ruins good business.

It's more like if I decide to pay you $300k because I'm pretty sure you'll do great work. If you then turn in a performance no better than a guy I pay $150k, then I'm going to go "oh shit, I was wrong and should pay you a lot less".

The stock market is all about expected future performance. Nobody forces companies to be publicly traded. If you don't want to deal with the expectations game then don't sell shares of your company to outside parties who generally don't care about your actual business.

Or, worse, you have a Really Damn Good Year, but I ding you at your performance review. Even though you were the best you've ever been, and better than your peers, you weren't quite as good as I was hoping you to be, so ... sorry, no raise this year.

On the other hand, you got the raise at the point where I started hoping you'd do great, even if you hadn't yet.

Maybe. It's really hard to set a fair baseline for a performance bonus; being given stock options struck at the current price is a very similar exercise.

I'm not sure I agree with your "bought stock in your job" example.

A better analogy would be: - your performance is great - your boss tells you that you'll get a promotion next year if you keep it up - your performance takes a turn for the worse - your boss tells you your performance is worse and lets you know that the promotion next isn't a sure thing

The stock market is a market that allows people to buy and sell stock at the price they see fit. The market should reflect all available information. I don't see any reason why LinkedIn's stock shouldn't plummet if suddenly their growth prospects went from "spectacular" to "so-so".

The analogy would likely be better if, rather than firing him, you docked his pay.

Every publicly traded company is subject to the other side of the coin too: their stock price rises based on exceeding analysts' expectations. If you want to be publicly traded, then you have to deal with your performance relative to the public's expectation.

But it's an aggregation of sentiment, not just one person.

And if you feel that sentiment is wrong, there's your chance to make money! Start buying stock in that business at the low price the "fools" have set.

Try to avoid concepts like "fair" and "unfair" when dealing with the market. I think this correction is an over-reaction to the guidance and the stock looks like a good buy to me right now.

By all metrics the business is doing great, but stock holders demand more growth and act irrationally over "sentiments". This is not reasonable or sustainable.

No. I think it's other way around. They were priced so high in the first place because they were expected to grow at a very high pace. They have mostly matching those until 15Q4 but the expectations for the next year are drastically lower so they get priced lower. What's so difficult to understand about it.

If you feel LNKD is cheap at this price, it's time for you to go make some money. Buy stock, calls.

Has LinkedIn even had any positive EPS yet?

From what I can tell it has, but I'm not a financial expert.

It wasn't that the Q4 earnings weren't up to snuff, they were, they exceeded expectations. It's that LinkedIn lowered it's predictions for next year.

The job networking site said that revenue for first quarter of 2016 is expected to be $820 million and adjusted earnings per share will be 55 cents. For the full year, revenue is forecasted to be about $3.6 billion. Investors were discouraged by these numbers, because they were expecting $867 million in revenue for the current quarter and $3.9 billion for the full year.