The American Underground is touting an announcement – what it calls a “game changing day” on Wednesday. And members of the startup community are tweeting their guesses about what’s up.

However, spokespeople for the Underground won’t comment about what’s happening – on the record.

A website has been hyping the event for several days, including a timer clicking down to an announcement that’s due some time after 11 a.m. on Wednesday.

Chris Heivly, one of two partners running The Startup Factory, posted a blog item Monday that hinted at what the announcement confirms:

“Would you like to hear an announcement that propels us into the next startup level?

“Would you like to share that with your peers, co-founders and other Triangle-ites?

“I can’t tell you more and I can’t be there as I will be in a major US City to kick off the announcement but you should be there. And did I mention the free lunch?”

However, the Underground says through a spokesperson that the “free lunch” is by invitation only.

The event will take place at the Bay 7 venue at the American Tobacco Historic District. 

On the website, the Underground says:

“ONE HUNDRED STARTUPS.

 ”ONE GAME CHANGING DAY. SEPTEMBER 25″

“One hundred” refers to the number of tenants at The Underground and @Main. 

Speculation among various Tweeters includes a possible expansion of the Underground.

The American Underground is a shared office space complex at the American Tobacco Historic District in Durham. It also operates @Main in Durham and is creating a new space in Raleigh.

American Tobacco and the Underground are owned by Capitol Broadcasting, the parent firm of WRALTechWire.