Do you remember 2016? Barack Obama was in the White House, the Zika virus was the looming threat, Disturbed’s “The Sound of Silence” was raging in the rock charts and Apple –yes, the Apple– was a value stock.

In fact, none other than value stock aficionado Warren Buffett went on a buying spree starting in the first quarter of 2016. By all metrics that determine future returns, Apple (AAPL) was considered an ideal investment throughout the period of Berkshire’s big purchases, which lasted until the first quarter of 2018. Let’s take the midpoint of that period, June 2017. Back then, based on fundamentals, Apple bore little resemblance to the current version that commands a super-premium price and gets such fabulous projections on Wall Street. Instead, it had all the qualities of a great value stock. Its market cap was $750 billion, and it was on track to post GAAP net income of $47 billion in fiscal 2017 (which ended September 30).

That left the P/E ratio at a low, unloved 16. As it does today, Apple returned virtually all of its profits to shareholders in the form of dividends and share buybacks. Shareholder return is made up of three components: earnings growth, total return from dividends plus share buybacks, and changes in the P/E multiple. Because Apple’s price was so low relative to its earnings, the company could boast a 1.7% yield, and the share buybacks provided an additional 4.4% boost as the remaining shares received a larger share of the profits. So investors received 6.1% from those two sources combined, plus future earnings growth, assuming the multiple stayed well below the market average.

These numbers set the bar for high returns extremely low. To reach 10%, Apple only had to increase net profit by 3.9%, as the combination of dividends and buybacks already contributed 6% or more. without any increase in earnings. Achieving that bogey of just under 4% meant annual earnings growth of around $2 billion. Achieving that goal seemed like a no-brainer. Plus, any increase in the battered P/E ratio would provide additional upside.

For several years, however, Apple’s profits remained stuck in the $50 billion range. Then, in the pandemic economy dominated by home offices, sales of laptops and other essential devices for remote work exploded. As of fiscal 2022, Apple reported annual profits of nearly $100 billion, double what it had three years earlier.

The problem: Apple’s market capitalization was rising much faster than even the huge swings in earnings. By mid-June of this year, the company’s valuation had risen to $3.2 trillion, more than four times its mid-2017 value. Put simply, Apple’s earnings doubled and its market capitalization quadrupled, increasing its P/E ratio from a modest 16 to a massive 32. What was once a deep-value company had become the model of a super-high-priced tech race car company.

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Apple stock forecast

Apple’s rise in share price has greatly reduced the impact of dividends and buybacks. The yield has fallen from 1.7% in mid-2017 to a paltry 0.48% today. Buybacks now contribute another 3.1%, significantly less than the 4.4% when Buffett bought shares. Together, the two factors give a base of just 3.6%, less than two-thirds of the old 6.1%. So to achieve a 10% return in the future, Apple needs to increase earnings by the difference of 6.4% (the 10% target minus 3.6% from dividends plus buybacks). Of course, this formula assumes that the P/E ratio stays at the current multiple of over 30.

How many billions does it take to increase profits by 6.4% annually? The answer: $6.4 billion on top of today’s base of $100 billion. That’s more than three times the $2 billion it needed in mid-2017. This is where Apple is breaking the law of large numbers. At current margins, the company would have to increase its sales by around $25 billion annually just to achieve that 10% return. What it takes to add corresponds to 12% of the average annual in total Revenue over the past three years. From the end of fiscal year 2021 to fiscal year 2023, Apple’s revenue grew by only $2.3 billion.

In short, Apple will face an uphill battle to maintain earnings growth of 6% annually from a gigantic base of $100 billion. But the company faces a second problem: the likelihood that its P/E ratio will not stay anywhere near its current level of 32.3. That’s the number for a turbo-growth company, not a mature company like Apple.

9So let’s assume that Apple does indeed grow its earnings by the 6% we require, which combined with dividends and buybacks would produce a 10% return assuming no change in valuation. In that case, the company would generate GAAP net income of $120.5 billion by fiscal 2027.

However, let’s say the P/E ratio drops to 20, which is still above the long-term average for the S&P 500. Buybacks would help by increasing earnings per share by about 10%. But that’s not enough. Even with the earnings jump and the buybacks, the company’s shares would trade for about $175, 17% below today’s price.

Therefore, Apple faces two formidable challenges when it comes to rewarding its investors. First, it will be difficult for the company to grow its profits from the $100 billion mark – a figure that doubled after the pandemic – fast enough to offset the now low contribution from buybacks and dividends. The second, related problem: Only companies that promise big earnings growth can sustain huge multiples, and at its current size, Apple looks more like a workhorse than a sprinter.

This story originally appeared on Fortune.com