Facebook Has a Ton of Users -- Can It Keep Making More Money From Them?

Buckle up, Facebook investors, because things are about to get pretty … predictable.

That’s right. It’s Facebook earnings day, which means the company will report its Q4 and 2015 year-end earnings results after the stock market closes Wednesday afternoon.

Over the past three years, Facebook’s earnings have become rather mundane. Each new report seems to follow the same pattern: Facebook’s user base increases, mobile revenue becomes more prominent and, more recently, its video totals jump off the page. This is no knock on Facebook, of course. The company does a nice job of tempering Wall Street’s expectations and then delivering on them. Wednesday’s earnings forecast calls for more of the same.

There is one key metric we’ll be looking at, though: ARPU, or average revenue per user, the metric that captures just how much money each Facebook user brings in for the company.

Why is that key? Facebook is massive — 1.55 billion users at last count — and while it’s still growing, its growth rate is starting to plateau. When growth slows, it means that Facebook will need to make more money from the same group of users in order to sustain its expected revenue growth. ARPU gives us a glimpse into whether or not that’s happening.

That number has been growing steadily, like most other parts of Facebook’s business. Facebook’s ARPU grew 10 percent in Q2, and 7.6 percent last quarter. It’s unclear what it will be this quarter, but Q4 usually provides a revenue spike given the intensity of holiday advertising, so a comparable jump in Q3 (if not more) seems like a reasonable expectation.

There are a few other ways Facebook could throw everyone for a loop on Wednesday. It could break out Instagram revenue numbers following its first major advertising push on the platform last fall. It could also share early sales figures for its Oculus Rift virtual reality headset, which opened for preorders in early January. That sale seems to be going fine if you look at expected shipping dates. At launch, units were expected to ship in March. Now, Oculus units won’t ship until July, which shows there may be some demand there.

Unfortunately, you shouldn’t expect serious sales or revenue updates on either part of the business. Facebook has made no indication that it will update those numbers, and analysts don’t appear to be expecting them either.

Here’s what analysts do expect: Profits of 68 cents per share on revenue of $5.37 billion for Q4, a revenue jump of nearly 40 percent year over year. That equates to $17.45 billion in revenue on the year, also a 40 percent jump. RBC Capital’s Mark Mahaney anticipates Facebook’s user total will grow by 30 million people over last quarter to 1.58 billion people, a 13 percent increase over last year.

We’ll be listening to the call in case something crazy does happen. The earnings are set to drop just after 4 pm ET and the earnings call is at 5 pm.

This article originally appeared on Recode.net.