Alibaba is the biggest company in the world, and you might not have even heard of it. The Chinese e-commerce company focuses on business-to-business sales, but it is really more like a super mutant hybrid of Amazon, eBay and PayPal — and it's worth more than all of them. Earlier this week, they filed prospectus papers on their upcoming IPO that is expected to be the biggest offering in history.

Alibaba is broken into several parts: Tmall is the online shopping section (Amazon); Taobao allows small Chinese companies to sell straight to consumers (Amazon/Ebay); and Alipay is a form of digital payment that Chinese shoppers use through their mobile phones (PayPal). Alipay also operates outside of Alibaba.

Last year, Alibaba sold $248 billion worth of products. They once saw $5.8 billion in sales in one day. Alipay processed $519 billion in payments. Analyst believe that post-IPO, the company will be worth between and $136 billion and $245 billion. 

Alibaba has not yet released how many shares they will trade, set a price range, or said which exchange the stock will be traded on, so we can't know for sure exactly where it land on the list below. However, most experts believe that it could surpass not just the biggest tech IPOs of all time, but the biggest IPOs ever. (The largest ever was the Agricultural Bank of China, which raised just over $22 billion.) That's why it is being called "the granddaddy of all IPOs," by Sam Hamadeh, CEO of PrivCo, a company that researches privately held corporations.

Here's the competition they're up against for world's and China's largest IPO: 

RNGS Reuters