NEW YORK (TheStreet) -- Shares of Apple (AAPL) - Get Report are flat in morning trading today as Citigroup reiterates its "buy" rating and $135 price target.

"We believe consensus estimates will continue to see upward revisions. Consensus is underappreciating the upgrade potential of Apple's installed base as new carrier actions make upgrading one's device materially easier, thereby diminishing the consumer device dilemma," analysts said.

"While we recognize Samsung (SSNLF) , Lenovo (LNVGY)  and several white box handset makers are selling products at materially lower prices, we believe the Apple ecosystem keeps customers in the Apple ecosystem which does not end, but rather only begins with one product and generally results in additional future products and services [such as] iTunes, App Store, Apple Pay," analysts added.

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As Apple shares are nearing all-time highs, Citigroup believes that shares can trade even higher, bolstering their "bullish" thesis with five key reasons: "device acceleration, attractive valuation, gross margins permanent step up higher, Apple Pay plus Passbook, and enterprise opportunity."

Apple has a consensus "buy" rating. Read here why one analyst says holding Apple stock is still a "no-brainer" despite its big gains.

Separately, TheStreet Ratings team rates APPLE INC as a Buy with a ratings score of A+. TheStreet Ratings Team has this to say about their recommendation:

"We rate APPLE INC (AAPL) a BUY. This is based on the convergence of positive investment measures, which should help this stock outperform the majority of stocks that we rate. The company's strengths can be seen in multiple areas, such as its solid stock price performance, impressive record of earnings per share growth, compelling growth in net income, revenue growth and notable return on equity. Although no company is perfect, currently we do not see any significant weaknesses which are likely to detract from the generally positive outlook."

Highlights from the analysis by TheStreet Ratings Team goes as follows:

  • Powered by its strong earnings growth of 47.72% and other important driving factors, this stock has surged by 65.17% over the past year, outperforming the rise in the S&P 500 Index during the same period. Regarding the stock's future course, although almost any stock can fall in a broad market decline, AAPL should continue to move higher despite the fact that it has already enjoyed a very nice gain in the past year.
  • APPLE INC has improved earnings per share by 47.7% in the most recent quarter compared to the same quarter a year ago. The company has demonstrated a pattern of positive earnings per share growth over the past two years. We feel that this trend should continue. During the past fiscal year, APPLE INC increased its bottom line by earning $6.43 versus $5.66 in the prior year. This year, the market expects an improvement in earnings ($8.58 versus $6.43).
  • The net income growth from the same quarter one year ago has greatly exceeded that of the S&P 500, but is less than that of the Computers & Peripherals industry average. The net income increased by 37.9% when compared to the same quarter one year prior, rising from $13,072.00 million to $18,024.00 million.
  • Despite its growing revenue, the company underperformed as compared with the industry average of 30.7%. Since the same quarter one year prior, revenues rose by 29.5%. Growth in the company's revenue appears to have helped boost the earnings per share.
  • Current return on equity exceeded its ROE from the same quarter one year prior. This is a clear sign of strength within the company. When compared to other companies in the Computers & Peripherals industry and the overall market, APPLE INC's return on equity exceeds that of the industry average and significantly exceeds that of the S&P 500.
  • You can view the full analysis from the report here: AAPL Ratings Report