Ask anyone who the world's richest person is, and you'll likely get a response of Bill Gates, Carlos Slim, or Warren Buffett. It turns out those are Nos. 1, 2, and 4, and the person ranking third will likely surprise you.

Buffett has a fortune hovering around $59 billion according to the latest estimates, and the mogul of Mexico, Carlos Slim, is worth an estimated $68.9 billion. Yet the man splitting the two is Amancio Ortega, whose net worth is said to be at $65.4 billion.

Sig

To put that in perspective, that's more than the reported fortunes of Jeff Bezos of Amazon and Mark Zuckerberg of Facebook, combined ($63 billion):

Who is Amancio Ortega?
An article in Fortune once noted that Ortega is "difficult to know, impossible to interview, and incredibly secretive," so there's good reason that he's not a household name like some of the others who are among the richest people in the world. 

Yet interestingly enough, the clothing company he founded and still owns nearly 60% of is actually the world's largest clothing company. So while he may not be well-known, you may be wearing one of this products.

Zara By Paco Seoane

Source: Paco Seoane.

Ortega is Spain's wealthiest man, and he founded Inditex, which is the parent company of retailer Zara, almost 40 years ago. He began his career as a clothing manufacturer in the 1960s and early 1970s as he steadily grew his operation to include multiple factories. Then in 1975, the first Zara store was opened, and Ortega's empire has been growing ever since.

Yet despite the massive fortune he accumulated over the last five decades, Ortega has been notoriously content with avoiding the public spotlight, and the first photograph of him wasn't published until 1999.

The clothing empire
Inditex now has 6,249 stores across the globe, with more than 1,800 from its flagship Zara. It had 47 stores in the U.S at the end of October last year. In total, its empire spans more than 85 countries. In 2012, it had more than 120,000 employees and 15.9 billion euros (roughly $21.5 billion) in sales. Through the first nine months of 2013, it has seen sales grow by 8% after factoring out currency impacts. 

Zara By Aurelijus Valeisa

Source: Aurelijus Valeiša.

The company is said to have two simple rules: Ensure customers get what they want, and they get it fast. This mantra has led to astounding growth, as sales have grown on average by 11% annually since 2008. Even more astonishing is the reality that from 2009 to 2012, it averaged more than one store opening each day, opening 1,745 stores in 1,461 days.

This unearthly growth and success has led to the massive fortune that Ortega has amassed, yet it has been reported that he has remained modest, as he eats in the company's cafeteria and even wears the same thing to work each day. 

Unfortunately, investment advice and business tips from Ortega are few and far between, but if we can learn anything from him, it's that massive fortune doesn't always have to mean massive fame, and seeking to satisfy the customer first is always a great place to start.

One billionaire who is happy to share
While Oretga has shunned the spotlight, Warren Buffett has embraced it. In fact, while he has made billions through his investing, he wants you to be able to invest like him. Through the years, Buffett has offered up investing tips to shareholders of Berkshire Hathaway. Now you can tap into the best of Warren Buffett's wisdom in a new special report from The Motley Fool. Click here now for a free copy of this invaluable report.

Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.