They don't compete in the same industry, but Apple (AAPL 7.24%) and Coca-Cola (KO 0.37%) share many similarities as investment candidates. The companies own two of the most valuable brands on the planet, helping them command huge profit margin advantages over their peers. And they are cash-generating machines, which gives their management teams extra resources they can direct toward stock buybacks and a growing dividend payment.

Coca-Cola and Apple are both favorites of billionaire investor Warren Buffett, too.

With those similarities in mind, let's stack the two companies up against each other as dividend investments.

Profit margins

Apple and Coca-Cola generate similar profit margins that reflect their premium industry positions. Coke's 30% operating profitability is about double PepsiCo's result. Apple, meanwhile, earns 10 percentage points more than peers like Garmin who compete in the tech device space.

Apple has a much better shot at improving on this metric over the coming years. Some of its fastest growth is occurring in the services segment, which includes subscription products like its streaming music platform. As the business tilts in that direction, investors are looking for Apple's margins to move toward more software-focused tech giants like Microsoft and its 40%-plus margin.

Coke shareholders can expect more modest margin expansion in the coming years due to the maturity of its industry. The beverage giant will get help from its push into more premium products like energy drinks and alcoholic beverages. Yet its earnings growth options are limited.

Cash flow and dividend yield

Coke is the clear winner when it comes to instant income. You'll get a 3%-plus yield from this stock, which is more than double the yield you'd get from owning the S&P 500 through an index fund. It's easily one of the biggest yields in the consumer staples industry as well.

Apple stock pays a relatively paltry 0.6% yield, in contrast. That's enough to put the iPhone maker above other members of the "Magnificent Seven," though, except for Microsoft.

Cash flow is solid at both companies, but Apple easily wins this matchup. The tech giant is generating more than $100 billion of free cash flow annually compared to Coke's $10 billion. Most of those excess resources are going toward attractive growth investments like product innovation.

Apple is also spending aggressively on stock buybacks. But at some point in the future, the tech titan will be free to shift its capital returns more toward dividend payments.

The better buy

Shares of Coke and Apple have underperformed the market in recent months, making them relative bargains compared to their peers. As a dividend investor, your choice between the two will mostly come down to your preference between growth and stability.

Coke offers one of the most dependable dividends in the market, a payout that's risen in each of the last 61 years. The company's sales are highly stable as well and don't tend to fall hard even during recessions. And you'll get a much higher yield from owning the beverage stock today.

In exchange for less stability and a smaller starting yield, Apple stock delivers some tantalizing advantages, mostly in the form of growth opportunities. Its dividend has more than doubled in the past decade, and the tech giant's gushing cash flow and improving margins suggest it could maintain that fantastic growth pace in the years ahead.

While Coke checks more boxes for dividend investors, consider Apple for its potential to mature into a fantastic income investment in the future.