November 15, 2021: -Tesla CEO Elon Musk said high production and breakeven cash flow will be the actual test for rival carmaker Rivian, which had a blockbuster IPO on Wednesday and has a market value of more than $100 billion.

“There have been hundreds of automotive startups, both electric and combustion, but Tesla is an American carmaker to reach high volume production & positive cash flow in last 100 years,” Musk said in a tweet Thursday.

It is saying it has 55,400 pre-orders for its R1S SUV and R1T pickup truck and a contract to build 100,000 electric vans with Amazon by 2030.

But trusting Rivian to assemble the vehicles and deliver them profitably represents a massive gamble for investors who already value the company higher than traditional auto giants Ford and General Motors.

Despite the lack of revenue, Rivian raised nearly $12 billion in its market debut, which makes the IPO the largest in the world this year. The IPO made Rivian the next most valuable car manufacturer in the U.S. behind Tesla.

After its two days of trading in 2010, Tesla had an over $2 billion market cap. Meanwhile, R.J. Scaringe, the CEO of Rivian, was worth that much on his own after his company’s other day on the public market.

Rivian shares popped 57% in their two days on the Nasdaq. Scaringe, who founded Rivian in 2009, owns 17.6 million shares, valuing $2.2 billion, based on Thursday’s stock price of $122.99.

“We started to think about the truck, SUV, and crossover segments as they presented a massive opportunity for us to demonstrate how a clean sheet, the technology-focused vehicle could eliminate long-accepted compromises,” Scaringe wrote in the company’s IPO prospectus.

“We wanted to establish our brand which delivers a combination of efficiency, on-road performance, off-road capability, functional utility, and product refinement that didn’t exist in the market.”

Rivian poached numerous former Tesla employees, including critical engineers who helped build the Tesla Model 3.

It’s not the beginning that Musk has thrown shade at Rivian. Last month he tweeted, “prototypes are trivial compared to scaling production and supply chain.”