Durham's reputation as a hub for start-up companies is getting a boost.

The American Underground, an incubator for up-and-coming businesses, is adding 22-thousand square feet of space on Main Street. Underground strategist Adam Klein says the expansion is good for young businesses and the Bull City.

"We see the move as important to downtown's entrepreneurial ecosystem as we are going to add another fifty start-ups to downtown with the main street expansion in addition to the eighty companies that are already here."

Klein says many of the businesses that located in the original Underground space two years ago have already raised venture capital and moved on.