For Apple, Services Segment Beginning To Outshine The iPhone

According to Moskowitz, Apple's Services business segment continues to be a growing topic of interest among investors. The analyst argued he could turn incrementally bullish on Apple's stock if the company is able to both show a sustainable year-over-year growth rate of 20 percent and decouple from iPhone and other device sales.

But for the time being, the relationship between iPhone sales and Services makes the analyst "somewhat skeptical" that a decoupling could occur, as the analyst's estimates see the correlation between iPhone unit growth and Services revenue growth at 0.84.

Services Growth 'Not Enough'

"Services growth is good but not enough," the analyst wrote. "Although services revenue could unlock valve for the model and stock longer term, the segment remains too small to move single handily the consolidated revenue needle when compared to iPhone."

Moskowitz further noted that during the calendar year 2016, Apple's Services revenue rose 20.3 percent year-over-year to $25.5 billion and represented 11.7 percent of total revenue. Meanwhile, iPhone sales account for 63.9 percent of revenue, but as iPhone sales services slow, Services could follow suit.

Bottom line, the analyst believes the nature of the relationship between iPhone and Services implies if iPhone sales continue to mature, growth in Services could dip below his desirable rate of 20 percent year-over-year.