Apple poised to report another record-breaking quarter by Philip Elmer-DeWitt @FortuneMagazine October 18, 2011, 12:17 PM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons Setting the stage for a monstrous Christmas selling season AAPL's 3-month roller coaster ride It’s been a busy fortnight for Apple AAPL , between the Let’s Talk iPhone special event, the death of Steve Jobs, the launch of the iPhone 4S and Sunday’s star-studded memorial service. Next week we’ll get the worldwide laydown of Walter Isaacson‘s Steve Jobs, the only biography written with Jobs’ cooperation, launching another round of media overkill (starting with next Sunday’s 60 Minutes). But today is about Apple Inc., the business that Steve Jobs built. When the markets close this afternoon, company will release its earnings report for the fourth quarter of fiscal 2011, giving analysts a peek inside the economic engine that has made Apple the most valuable company on the planet. Holiday quarters are traditionally Apple’s biggest. But Q3 smashed the records set last December, and most analysts (53 of the 58 we polled) expect Apple to report Q4 revenues that top the record $28.57 billion set in July. With the new iPhone 4S, the iPad 2, strong Mac sales and seasonal iPod gift-giving, this coming Christmas could be off the charts. When Apple posts its results after the markets close today, we’ll be watching the usual metrics: Revenue and earnings per share (the top and bottom lines) Gross margin (a measure of how efficiently a company turns sales into profits) Unit sales for Apple’s four key product lines (all but the iPod should set new records) Guidance (investors have learned to expect Apple to guide pessimistically, but could react positively to any uncharacteristic signs of optimism) Here’s the cheat sheet we’ll be using to make sense of the results as they come in: Sources: Company reports, analysts' reports Key: The actual results from Q4 2011 and Q3 2010 are used to calculate year over year and sequential growth, respectively. Apple’s guidance is for your amusement. Thomson Financial averages the estimates of 44 unnamed analysts; it’s what the press usually refers to as “the Street’s consensus.” We identify by name and affiliation the 42 institutional and 16 independent we poll (there are listed here). Our “whisper number” is the average of the six analysts with the best track record over the past year (see here). Look for Apple’s earnings to cross the business wires at about 4:30 p.m. EST. The company has scheduled an hour-long earnings call with analysts at 5:00 (webcast here). We’ll listen in on the call and post some quick analysis tonight. Wednesday morning, we’ll analyze the analysts in our quarterly Earnings Smackdown.