The company that first achieves a $1 trillion dollar market capitalization will own a psychological milestone for corporate history. But depending on which company you think can claim that crown, even the highest valued today will still amount to at least a 100% return on investment.

So what does the competitive landscape for reaching a trillion look like?

Law of large numbers
One thing to note before looking at specific contenders is how large companies have to fight harder as they become larger. For example, Warren Buffett's $280-billion Berkshire Hathaway (BRK.B 0.05%) must look for larger deals to make a noticeable dent on its returns on assets. As Buffett wrote in his 1998 letter to shareholders:

Berkshire's capital base is now simply too large to allow us to earn truly outsized returns. If you believe otherwise, you should consider a career in sales but avoid one in mathematics (bearing in mind that there are really only three kinds of people in the world: those who can count and those who can't).

So when viewing potential trillionaires, look for companies with truly exponential growth opportunities. If sales remain at the same dollar level, as a growth percentage they will fall, investors will not pay up for previous price-earnings ratios, and the company's market value won't grow.

The top dogs
The highest-valued companies of the day are typically the ones that investors think have the most potential for continuing growth. This would be Apple (AAPL 0.16%), ExxonMobil (XOM -1.07%)Google (GOOGL -0.28%), and Microsoft (MSFT -0.27%). Popular sentiment points to the greatest opportunities for Apple and Google. Google's potential lies in its wide-appeal projects that have yet to scale and return profits, like autonomous cars and Google Glass. Apple's prospects are tied to its future ability to surprise with revolutionary products. Yet investors have been waiting several years for such a new product while the iPhone continues to contribute a bulk of Apple's revenue.

If either of these companies made it to a $1 trillion valuation, at an ultra-conservative price-earnings of 8, what would their sales need to be at their current net profit margin, both around 20%? For both companies, this means sales of $625 billion. Right now, Google has sales of around $50 billion and Apple around $170 billion. For Google, earnings per share would need to be $374 compared to today's $35 per share. And Apple would need to take in $139 per share, compared to today's $40 per share. Right now, Apple is closer to attaining these numbers, though it still means tripling its earnings per share. It seems like a long way until either company makes it to a trillion-dollar valuation.

What might be more likely is a company that has yet to make a name for itself reaching one trillion. It only took a decade for Google to reach $200 billion in value, and less than 15 years to reach $375 billion. Meanwhile, Apple was worth less than $100 billion during the recession in 2009, and in four years reached over $600 billion in value.

With technology enabling faster changes to established industries, the rotation of top-valued companies could speed up, creating a vastly different perspective in a short timespan. In the meantime, Apple and Google have plenty of earnings to generate to reach anywhere close to the trillion mark.