Apple stock ticked slightly higher on Thursday as analysts begin to consider what 2018 might bring for Cupertino. One big factor this year is the $29 battery replacement the company is offering to users of many older iPhone models, an olive branch extended to buyers in an attempt to make up for the lack of disclosure about the fact that it was slowing older iPhone models deliberately to fix a problem.

Another major factor for Apple stock this year will be Trump’s tax reform bill, which not only saves the company piles of money but also enables it to repatriate cash at rates it can’t ordinarily.

Apple stock still hangs on iPhone sales

Because Apple stock movement is heavily dependent on iPhone sales, anything that could impact how many iPhones the company can sell will impact its stock price. As a result, the cheap battery replacements could have a negative impact on Apple stock indirectly.

Barclays analyst Mark Moskowitz warned in a recent note on Apple stock that his firm’s August survey found that battery drain is the top reason users upgrade to a new device. As a result, some of those who were intending to upgrade to an iPhone X might change their minds and opt for a $29 battery replacement rather than a $1,000 iPhone.

He continues to believe that iPhone unit estimates are too high and maintains his Neutral rating and $162 price target on Apple stock.

Cheap batteries could cost Apple $10 billion

Moskowitz estimates that about 75% of the roughly 675 million iPhones being used currently would be eligible for the reduced price on the battery replacement and could actually be in need of the new battery. Because of how large the iPhone user base is, he warned that “even a small percentage” deciding on a new battery instead of a new iPhone may have a “meaningful impact on iPhone sales.”

The Barclays analyst estimates that a little over 10% of those whose iPhones are eligible for a $29 battery will replace it, and about 30% of those who replace the battery will keep the iPhone instead of buying a new one. He also estimates that battery revenues on 54 million iPhones would amount to about $1.6 billion, but Apple would exchange more than $11.9 billion in iPhone sales for that measly amount, in his estimation, based on an average selling price of $740.

Another iPhone-related problem for Apple stock right now is the lack of clarity around how iPhone X sales are going. Lots of analysts are guessing at the mix of iPhone models, but we won’t have any real concrete evidence until Apple’s next earnings report, either late this month or early next month.

Tax reform a benefit for Apple stock

It’s not all bad news for Apple stock, however. The tax reform bill is considered a win for the iPhone maker and all the other tech firms that keep their cash hoards overseas to reduce their tax liabilities. In a note on Thursday, GBH Insights analyst Daniel Ives pegged the amount of cash held overseas by “a handful” of large-cap tech firms at between $550 billion and $600 billion. He believes that $300 billion to $400 billion of this overseas cash will be repatriated in 2018 and estimates that Apple along accounts for about $200 billion of it.

He also considered what Apple might do with the cash it repatriates and echoed the suggestion that the company could try to buy Netflix as part of a “content arms race.” He feels that this is the right time for such an “aggressive move,” recalling questions that have been swirling for years about what Apple will do after the iPhone is done.

Apple stock closed up 0.46% at $173.03 on Thursday.