It ends this week. Investors might as well get ready for the negative headlines.

Click twice to enlarge. Source: Posts at Eventide

FORTUNE -- The bad news is that every analyst we've surveyed -- even the most bullish -- believes that for the first time in a decade Apple (AAPL) will report that its income this quarter was lower than the same quarter the year before.

According to Thomson Financial, the consensus EPS for fiscal Q2 2013 on Friday was $10.18, down from $12.30 in Q2 2012. The analysts we've heard from so far are even more pessimistic. Their estimates range from a low of $9.23 to a high of $10.39 for a mean EPS of $9.85.

The good news for investors is that Wall Street seems to have already priced this negative income growth into the stock. Judging from the performance of Apple's shares since early March, the smart money has been pouring back into the company for the past three weeks.

So what's going on?

The problem for Apple is not that its business is collapsing. Indeed, the projected revenues of $41 to $43 billion Apple offered analysts in its quarterly guidance would represent another record second quarter for the company.

Rather, it's what analysts call a "tough compare" in terms of gross margins -- a measure of the efficiency with which a company turns revenue into profits. Last year at this time Apple's gross margin peaked at an extraordinary 47.37%. This year, following the introduction of a slew of new products -- including new Macs, iPhones and iPads -- it is projecting gross margins somewhere between 37.5% and 38.5%. That's what's driving the income down. Wall Street seems to be betting that in the next six to 12 months, those numbers have nowhere to go but up.

It's all laid out quite clearly in a series of charts posted Saturday by Robert Paul Leitao, who manages at the Braeburn Group the world's largest and must bullish collection of independent Apple analysts. You can read his analysis of the quarter that ends this week at his website: Posts at Eventide.