By Chris Ciaccia

Apple (AAPL) is one of Wall Street's most beloved stocks, with 50 of 58 analysts rating the stock "buy," and only one rating it a "sell." So it's noteworthy anytime analysts lowers their rating and it's really noteworthy when an analyst cuts his price target, citing concerns about decelerating growth.

Noted Apple bull Peter Misek of Jefferies has cut his price target on the Cupertino, Calif. company, pointing to worries that Apple's growth will slow, as well as potential negative margin leverage. Misek lowered his price target to $800 from $900.

Though he did not lower first-quarter estimates, Misek believes Apple's growth will start to slow down in 2014, as the markets become saturated with its products. He believes Apple will launch the iPhone 5S in June or July, compared to the September and October launches for the iPhone 5, and iPhone 4S, respectively. "Based on our checks, likely updates include a new super HD camera/screen, a better battery, and NFC. Possible updates include an IGZO screen for Retina+, 128GB storage, and coming in 6 to 8 colors," Misek wrote in his note.

Even though Apple may push up the iPhone 5S launch, which would boost earnings per share for fiscal 2013, Misek mentioned that very early 2014 iPhone build plans indicate a deceleration in growth to around 20%, as the market becomes saturated. Apple shares took a pounding last week on reports of a margin hike at one clearing firm and concerns over component supplies falling next year.

Apple shares have been under siege in recent weeks, falling 21.64% over the past three months, compared to a 5.04% decline in the Nasdaq ($COMPX).

There are also concerns over investments in next-generation technology and more expensive semiconductor transitions, which could hurt Apple's ability to leverage margin, and bring down the earnings multiple.

Misek cut his iPad estimates for 2013, as iPad mini supply continues to be constrained. He cut his calendar first-quarter estimates to 20 million, and lowered his full calendar year estimate from 116 million to 100 million.

There's also the potential for a pre-paid iPhone, something Misek touched on in his note. He believes Apple could release such a device, though no plans have been confirmed. "We believe there is a good chance that a low-cost iPhone could be introduced at the same event as the iPhone 5S. We believe the device would primarily be targeting pre-paid markets, and emerging markets, especially in Asia. We believe the device would have a $200-$250 price point," Misek wrote in his ntoe.

Apple shares started the week lower, but are now up 0.29% to $534.77 in late morning trading Monday.

More from TheStreet.com

• Apple is crashing but we're not all screwed!
• CEOs who will get fired in 2013
• 5 rocket stocks signaling buy this week