AAPL Chart

AAPL data by YCharts

Once again, Apple (NASDAQ:AAPL) stock has its investors bewildered. After peaking at around $135 per share earlier this year, Apple is now officially in correction territory, having sunk to its current level of $114 per share. That drop represents a 15% decline from Apple's 2015 intraday high, which is truly stunning, considering Apple is fresh off an earnings report that was nothing short of spectacular.

As is all too typical, Apple's fantastic business performance wasn't good enough to satisfy everybody. Expectations for Apple are always high, and the bar was set so high last quarter that the company's results were labeled a disappointment. This situation could scare individual investors into selling the stock, but that would be extremely misguided.

Apple's future remains bright, which is why selling now is the worst mistake a Fool could make.

Beauty is in the eye of the beholder
Apple's sell-off started shortly after its last earnings report. Shares of the technology giant fell 4% on the day the report was released, and the stock has continued to drift lower ever since, even though the underlying results were outstanding. Apple showed meaningful growth across virtually all the metrics that matter most.

All Apple managed to do last quarter was produce 32% year-over-year revenue growth, along with 44% earnings growth. Apple sold 47.5 million iPhones, a 35% year-over-year increase, and the average selling price for iPhones rose 17% to $660. Mac units sold increased 9%, and the only weak point was that iPad sales fell 18% year over year. 

Apple raked in $60 billion of free cash flow over the first nine months of the fiscal year, and its balance sheet is stuffed with $202 billion in cash and marketable investments.

These results are remarkable, yet the stock is falling anyway. But investors need to focus less on what the stock is doing and more on what the company is doing. In that regard, everything the company is doing is clearly working extremely well, and there are even better things on the horizon.

Too many catalysts to ignore
While short-term traders and the talking heads in the financial media obsess about whether Apple's quarter beat expectations by a wide enough margin, Foolish investors should keep focused on what matters: the long term. Going forward, there are far too many promising catalysts on Apple's horizon to sell the stock now.

Just a few of these include the newest iteration of the iPhone, the iPhone 6s, which should be announced as early as next month. Various media reports have also indicated that a new Apple TV is on the way as well. When you add this to the continued expansion of Apple Pay, and the increased penetration of the Apple Watch, it's easy to see why selling Apple stock now makes little sense. This is particularly true in light of the fact that Apple's valuation remains extremely modest.

New product launches will help keep Apple's revenue and earnings growing, and EPS will be further fueled by Apple's huge stock buyback program. The company bought back $22 billion of stock in the past three quarters combined, which helped lower its diluted share count by 4% over the past year.

Very few reasons to sell here
Apple is growing revenue and earnings at high rates, the stock is cheap, and the company has a mountain of cash on the balance sheet. Going forward, while it's true that Apple's fiscal 2016 earnings results will probably see a lull because of extremely tough comparisons, the stock is priced at 13 times trailing earnings per share, or just 9 times if you exclude the approximately $35 per share in cash and investments. Apple's 1.7% dividend is icing on the cake.

AAPL PE Ratio (TTM) Chart

AAPL P/E Ratio (TTM) data by YCharts

Apple's stock drop is due to multiple contraction, not declining fundamentals. In other words, investors aren't willing to pay as high of a price for Apple's growth. But investor sentiment can change quickly. It's likely the market will once again wake up and realize that Apple is a great business.

Selling a stock at such cheap multiples simply doesn't make sense from a long-term investment perspective. The goal is to buy low and sell high, not the other way around. If anything, Apple stock is a fantastic buying opportunity for Foolish investors.