Two tech stocks we're all familiar with may move in a big way this week -- either up or down. We're talking California-based Apple (NASDAQ:AAPL) and Facebook (NASDAQ:FB). Earnings reports for both companies -- Apple on Tuesday and Facebook on Wednesday -- follow two sharp year-to-date declines for both stocks. Could potentially optimistic reports help the stocks recover this week?

Here's some background on these stocks ahead of their reports this week.

Apple will be reporting its fiscal first-quarter results, which is the fourth calendar quarter of 2015. Investors are on edge ahead of the report because supply chain rumors suggest Apple's orders for key iPhone parts have been cut. This has led some analysts to believe the company's iPhone 6s cycle may result in a year-over-year decline in smartphone sales.

Image source: Apple.

Concerns about the iPhone 6s cycle means guidance for Q2, which will be provided in its first-quarter report, will likely be a key focus for investors.

CEO Tim Cook has previously urged investors not to read into supply chain reports. The sprawling global supply chain is too complex for investors to make any useful conclusions about the company's sales, he said in 2013.

Investors will find out next week whether their worries about iPhone 6s demand were justified.

For a more in-depth preview of Apple's earnings report, check out this analysis.

The pressure for Facebook to perform is as high as ever ahead of the company's fourth-quarter results next Wednesday. While the stock has pulled back recently, its stock price and price-to-earnings ratio are still considerably higher than they were a year ago. This higher stock price and steeper valuation mean the downside could be bigger if its report includes any red flags.

FB Chart

FB data by YCharts.

Investors will be particularly interested in whether the company can continue to sustain its impressive revenue growth. During Facebook's third quarter, revenue was up 41% from the year-ago quarter. This was surprising growth, as it was actually an acceleration of its 39% growth in Q2.

They will also be looking for updates on social platforms beyond its native Facebook network. Other platforms include the now-separated Messenger, WhatsApp, and Instagram.

Any updates on Messenger and WhatsApp may be particularly useful for investors at this point, as the two messaging platforms are undergoing some big changes as the company begins rolling out new ways for businesses and consumers to interact -- moves that CEO Mark Zuckerberg has indicated are a preview of the way the company will go about monetizing its messaging services.

Look for Facebook to provide an update on how its moves to connect businesses with consumers are playing out.

Here's a closer look at some of the key items to watch when it reports.

While there's a good chance both stocks could see big moves this week. There's really no way to guess which direction those moves will be. The market is an irrational place. But investors should consider actual results closely to see whether any big moves are justified.

Investors can take a look at Apple's and Facebook's quarterly results after the market closes on Tuesday and Wednesday, respectively. Both will also host a live earnings call shortly after results are released.