Facebook and Amazon have joined an exclusive club open to only the richest companies in the world: both crossed the half-a-trillion mark.

Facebook (FB) exceeded $500 billion in market value for the first time ever Thursday morning as Mark Zuckerberg's company continued its rapid ascent. Amazon (AMZN) hit the $500 billion milestone for the first time on Wednesday.

Only three companies, all in the tech industry, are worth more right now: Apple (AAPL) ($798 billion), Google parent company Alphabet (GOOGL) ($667 billion) and Microsoft (MSFT) ($571 billion).

The combined $1 trillion valuation for Facebook and Amazon shows just how euphoric Wall Street has become about the future for these tech juggernauts. The meteoric rise of their stocks -- each are up more than 40% this year alone -- further enriches these companies' visionary founders.

Jeff Bezos, 53, started Amazon in 1995 and just surpassed Microsoft (MSFT) co-founder Bill Gates on Thursday as the world's richest person, according to Bloomberg News. Zuckerberg, who is just 33 years old and is a Harvard drop-out, is now worth more than $69 billion, according to Forbes.

Related: Facebook's rapid sales growth is slowing down

Facebook's $500 billion milestone looks stunning considering the social networking giant has only been public for five years. But today Facebook boasts more than 2 billion users and generates the vast majority of its money from mobile phones. Savvy acquisitions have also given Facebook control of two of the most popular platforms on the web: Instagram and WhatsApp.

Wall Street seems to be largely unfazed by signs that Facebook may be nearing middle age. The company's stock soared 5% on Thursday even after it reported the slowest revenue growth in nearly two years.

Amazon has altered the way people shop, creating enormous turmoil for brick-and-mortar retailers in the process. The e-commerce behemoth continues to grow, with sales on this year's Prime Day shopping holiday spiking 60% compared with last year. Now, Amazon has set its sights on the grocery industry by agreeing to purchase Whole Foods (WFM) for nearly $14 billion.

With CNNMoney's Fear & Greed Index of market sentiment sitting in "extreme greed" mode, Wall Street is betting Amazon will reveal more explosive growth when it posts earnings after Thursday's closing bell.