With Apple's (AAPL -1.92%) $1 trillion market cap, many investors automatically assume it must be overvalued.

Don't make that mistake. Even now, with its stock trading near all-time highs, plenty of value remains in Apple's shares. In fact, here are four reasons you may want to consider buying Apple today.

Much more than just hardware

Bears often argue that Apple is essentially a hardware company that's destined to see its margins eaten away by the competition. I've been hearing this argument for more than a decade and it still hasn't come to fruition. More importantly, it's unlikely to be the case any time soon.

Apple has built one of the most trusted brands in the world. Its products are beloved by millions for their ease of use, beautiful design, and reliability. Apple has also created a powerful ecosystem comprised of its best-in-class smartphones, tablets, and computers. An ever-expanding suite of services such as Apple Pay, Apple Music, AppleCare, iTunes, iCloud, and the App Store all help to tie the company's devices together. This makes them more valuable to users. And once someone buys an Apple device, they tend to buy another. In turn, Apple enjoys a massive installed base of approximately 1.3 billion devices. 

These users provide ample -- and rising -- demand for Apple's services. In fact, services revenue surged 31% year over year, to $9.5 billion, in the third quarter. Better still, Apple is on track to surpass CEO Tim Cook's goal of generating nearly $50 billion in services revenue by 2020. 

Slowing iPhone unit sales doesn't mean revenue growth will stall out

Apple's staggering growth does come with some challenges. For example, with so many people already owning iPhones, future growth will be harder to come by.

Yet while iPhone unit sales may have leveled out, iPhone revenue continues to head higher. Apple is flexing its considerable pricing power with its latest batch of iPhone models, with the price of a fully-loaded iPhone XS Max reaching as high as $1,449. And with signs pointing toward strong early demand for its most expensive models, iPhone average selling prices should head higher in the quarters ahead. So although unit sales growth may be modest, iPhone revenue growth may continue to exceed investor expectations.

An apple with a bite taken out of it.

Apple's shares still look tasty at current prices. Image source: Getty Images.

An attractive valuation

Despite its booming services business and persistently strong iPhone revenue growth, Apple's stock currently trades at a substantial discount to the market. The company is trading for about 20 times trailing earnings, compared with nearly 25 times earnings for the S&P 500. That's a discount of approximately 20%.

I'd argue that Apple deserves a significantly higher earnings multiple -- at least in line with the market average -- particularly as recurring revenue from the services business becomes a larger portion of Apple's overall revenue base. That's because investors value certainty. The more confident they become that Apple can continue to generate sales and profits well into the future, the more they'll be willing to pay for its stock.

Moreover, the valuation gap between Apple and the market as a whole is even larger when we account for the company's massive cash reserves. With about $130 billion in net cash, Apple trades for less than 17 times earnings on an ex-cash basis.

For years, people argued that Apple's cash should be discounted by as much as 35% to 40% due to repatriation taxes. But that argument no longer holds true due to tax reform, which will allow Apple to bring overseas cash back to the U.S. at a far lower cost and therefore make it much easier to return a larger portion of it to shareholders via dividends and stock buybacks. As such, investors should begin to value Apple's cash hoard -- and, by extension, its stock -- more highly.

The best investors are buying Apple

Notably, Warren Buffett, CEO of megaconglomerate Berkshire Hathaway -- and perhaps the world's best value-focused investor -- recently said that he'd "love to own 100%" of Apple. Apple is far too large for that to happen, so Buffett has been doing the next best thing: steadily increasing Berkshire's stake in this still-undervalued business. In fact, Apple is now the largest holding in Berkshire Hathaway's $200 billion investment portfolio. 

Individual investors may wish to consider buying alongside Buffett and begin -- or add to -- their stakes in Apple today.