Presumably Rivian will need more money when they start to tool up production. Do you think an IPO is in the offing, or do their backers have sufficient additional capital, or will they be looking for additional private money?
It turns out their backers are interesting. The two main equity investors (Sumitomo, and Abdul Latif Jameel) aren’t just financial investors, they bring a lot of strategic value, especially in the automotive space. My guess is that Rivian will stay private, raising money on the private market for the next couple of years at least. Unlike when Tesla started, there is a deep private market investment pool right now, and as Tesla has proven, being public may bring more grief than positives.
An IPO will definitely be on the cards at some point. But until they can show they are delivering this won't happen. The investors will want their money back and more, and the best way to do this is through an IPO.