The competition for the second spot among the world's billionaires is intensifying again. Despite an almost $2.2 billion boost to his net worth in the aftermath of Amazon-Whole Foods deal, Jeff Bezos may or may not be the second wealthiest man in the world, depending on what your publication of reference is. While Bloomberg's Billionaires Index calculation of Bezos' net worth at $84.6 billion puts him in second place behind the world's richest man Bill Gates, Forbes magazine's real-time rankings pegs his wealth at $84.1 billion, trailing Europe's richest person, Amancio Ortega. (See also: Amazon Stock Gain Pays For $13.7 Billion Whole Foods Deal)

Ortega, the 81 year-old retail baron and Europe's richest man, whose empire is built on brands like Zara, saw his net worth increase by nearly a 1% on the back of a similar jump in the stock of Zara parent Inditex SA (MADRID: ITX.MC). Forbes estimates Ortega's net worth at $84.2 billion, while Bloomberg's calculations put him at $82.3 billion. Ortega also holds the distinction of becoming the world's richest man, surpassing even Bill Gates, for a brief time in a cat and mouse chase according to Forbes, as the shares Ortega's surged and fell last year.

Bezos became the world’s second richest man on March 29, 2017 surpassing Warren Buffett, according to a Bloomberg report. And yet, the following morning, the real time net worth calculated by Forbes at one point had Bezos tied with Warren Buffett (BRK.B) in the third spot. Since then, as the stocks of Amazon and Inditex have soared and fallen, Bezos and Ortega have toppled each other to claim and reclaim the second spot. Warren Buffett, with a current net worth of close to $76.5 billion has fallen far behind. 

The Difference Between Forbes and Bloomberg

Both publications compile their rankings by analyzing evidence of assets and liabilities. That means understanding complicated company structures, financial arrangements and evaluating out-of-the ordinary asset classes. Both publications broadly state similar methodology, relying on recent stock prices and exchange rate information for publicly-held companies. But the difference may be in the calculations of hard-to-assess assets. 

According to Bloomberg, Ortega owns 59.3% of Inditex and also has a vast global real estate investment in his portfolio. Inditex is the world's largest retailer which went public in 2001 and now commands a market cap of more than $110 billion. Forbes reports that Ortega typically receives annual dividends worth nearly $400 million. The company's stock price has increased 9.4% year-to-date and 21.32% over a one year period as of June 19, 2017.

In Bezos' case, he owns nearly 17% in Amazon which at current prices would be worth close to $82 billion. That has been a key driving factor in Bezos' wealth, especially since the share price crossed $1,000. That trend could continue with analyst predicting the e-commerce giant's market cap top exceed a trillion dollars. (See also: Amazon Will Win Race to $1 Trillion Market Cap: NYU Prof.)

What makes up of the rest? Bloomberg’s analysis includes cash he got from sale of shares since the 1997 IPO as well as his investments in space exploration company Blue Origin, The Washington Post and Business Insider. Public companies are usually only a part of the large fortunes that these individuals command, but information about private investments can be hard to come by. For example, the Bloomberg methodology arrives at valuations for privately owned companies by comparing enterprise value to EBITDA or price to earnings ratio. When information simply isn't available, Bloomberg makes calculations based on comparable peers, as does Forbes. The peer-based valuation may differ across the two publications simply based on the peers they select for valuing a particular asset.

Also, certain assets that are closely held have subjective valuations – like rare collections or equestrian farms. Lastly, cash holdings could get ambiguous without exact information from the source itself. While cash received from dividends could be derived from information available in the public domain, it is difficult to track how much cash these individuals receive or spend. Bloomberg uses a "hybrid return based on holdings of cash, government bonds, equities and commodities" for calculations for cash and other investible assets.

One other big difference in the lists: Michael Bloomberg is #10 on the Forbes list, but is nowhere to be found on the Bloomberg List because of an editorial policy that he "isn't considered for this ranking." Sometimes it's good to be the boss.