As shares of Cupertino, Calif.-based tech titan Apple Inc. (AAPL) surge 49.2% year-to-date (YTD) compared to the S&P 500’s 19.1% gain over the same period, one team of analysts on the Street sees further upside in shares moving forward into 2018.

While investors have rallied around the stock due to enthusiasm over the new 10th anniversary iPhone X product launch, Citi Research highlights several other fundamental growth drivers propelling the stock higher. (See also: Expect Less From FAANGs in 2018: Morgan Stanley.)

Citi analyst Jim Suva issued a note to clients on Wednesday reiterating his buy rating on the smartphone marker’s shares. He noted that while smartphone growth “remains tempered” the Wall Street bank continues to see positive tailwinds, most notably a potential tax reform and global growth. Suva expects Apple to gain nearly 16% over 12 months from $172.74 on Wednesday afternoon, reaffirming his $200 price target.

Mobile Firepower

The analyst expects Apple’s iPhone super upgrade cycle to continue into FY18 given production issues have resulted in elongated lead times compared to previous cycles. As a result, the company should see better-than-typical seasonal demand in the March quarter.

Secondly, Citi sees Apple as positioned to benefit on the GOP tax reform set to reduce the corporate tax rate and incentivize cash repatriation.

Suva wrote that Apple’s “sticky user base” should drive continued services revenue growth, forecasting continued momentum in mobile commerce, mobile gaming and mobile entertainment.

Looking to India

In the midterm, the analyst views enterprises’ push to upgrade mobile device hardware as a positive for Apple. Longer term, Citi believes that Applewood (Apple's strategy to boost traction in India and build out its services) will “eventually become material.”

Ultimately, AAPL stock is trading at an "attractive valuation" at a 20% discount to the S&P 500 and in line with its five-year median despite improving fundamentals, wrote Suva. (See also: Apple Needs Its Own Streaming Service: Bernstein.)