Now that the IPO market has reopened, traders are hopeful that an enormous pile of new stock offerings can be pushed through the door in 2019.

IPO observers are optimistic, and with some justification: There is an outside chance 2019 could be an all-time record for initial public offerings, passing even the legendary 1999 and 2000 years.

But for that to happen, a lot of things need to go almost perfectly. There can't be any more government shutdowns, market conditions have to exhibit low volatility and — most importantly — the public needs to have an appetite to buy very large IPOs at (potentially) very inflated prices.

That's a very tall order.

How big is the IPO market in 2019? Really big.

Renaissance Capital, which advises institutional buyers on IPOs and maintains the IPO ETF, a basket of roughly the last 60 large IPOs, has a watch list of 226 private companies that are planning to go public in 2019. These companies represent a value of $697 billion.

Assuming the companies float 15 percent of their value, you get over $100 billion in IPO offerings ($697 billion x 15 percent = $104.55 billion).

"That will break any record we have ever seen in terms of dollar volume," Kathleen Smith of Renaissance tells CNBC. It would be bigger than 1999 and 2000, the years that represented the height of the dot-com IPO boom. There were $93 billion of IPOs in 1999 and $97 billion in 2000, according to Renaissance Capital.

The market has never gotten close to $100 billion in capital raised in a single year since then. In 2014, the total value raised was $85 billion, but $22 billion of that was for Alibaba, the Chinese e-commerce giant.

In terms of deals lined up for this year, of the 226 companies set to launch there are 119 companies that would be classified as "unicorns," or private companies with valuations over $1 billion. This group includes well-known names like Uber, WeWork and Lyft.