America Online founder-turned-investor and philanthropist Steve Case and N.C. State Treasurer Janet Cowell will help the American Underground tech hub celebrate a strong year of progress in 2015.

At an event scheduled to begin at 4:30 p.m., Underground officials are set to unveil a report documenting just how much the rapidly growing hub – actually, hubs with multiple locations in Durham and Raleigh – and its tenants grew over the past 12 months.

Festivities will take place at American Underground at Main in downtown Durham.

Case is a big supporter of the Underground’s efforts and has made Triangle investments. He’ll be participating through a video link.

The annual report will be unveiled at 4:30 p.m.

Also participating will be Adam Klein, Chief Strategist, American Underground; Durham Mayor Bill Bell; Tatiana Birgisson, founder of Mati Energy, winner of the 2015 Google for Entrepreneurs Tech Demo Day; and other startup leaders.

The Underground launched six years ago.