Airbnb and DoorDash plan to go public in the next few weeks, capping off a very busy year for IPOs.

What's next: You ain't seen nothing yet.

• Other companies expected to complete IPOs before Christmas include fintech Affirm, gaming platform Roblox and e-commerce company Wish.

State of play: There are over 500 "unicorns," or upstart companies that are valued at $1 billion or more by venture capitalists, according to CB Insights. More than half of those are based in the U.S., and around two dozen are valued at more than $5 billion.

• Among some of the better known names are ByteDance (owner of TikTok), SpaceX, Instacart, Epic Games (maker of Fortnite), Coinbase and Stripe.
• Then there are the lesser-known cloud software companies seeking to become the next DataDog or Snowflake — valued at a combined $4.6 billion entering 2020, now trading with combined market cap of $130 billion.

"The real story of 2020 is that it's just the preview for 2021, especially if there's a vaccine and the economy roars back," a tech IPO banker tells Axios.

• Another banker, this one based in San Francisco, adds that he regularly participates in multiple "bake-offs" on the same day for large tech IPOs.

There's also been a recent boom in special purpose acquisition companies (SPACs), which represent another way for startups to go public — including those that might not be ready to do a traditional IPO, like many of the uncommercialized electric vehicle makers.

• Most of the SPACs formed in 2020 will seek out targets in 2021.

The bottom line: There used to be only a handful of unicorn IPOs per year, due to a limited pipeline, making each one a major Wall Street event. Those days are over.