The Dare Enterprises is a company owned by Mr. Dare, Rachel Dare's father. The company cuts down trees and other wildlife, so buildings (usually malls and car parks) can be built, which in turn, slowly killed Pan, the god of wilderness and nature, because of its excessive clear-cutting. It is a very successful company as shown on several occasions in the series.
When Rachel needs a ride around to find another way back into the Labyrinth, she uses her status as Mr. Dare's daughter to rent a car on the spot, even though the car was originally rented for someone else.
When Rachel is walking along the beach, on her vacation, she bends down to write something in the sand. It's in Greek, but she realizes what she writes: Perseus. She drops the stick she was using and runs back to the family's vacation house. She tells her father she needs to get back to Manhattan because there was trouble. They argue for awhile and Rachel makes a deal. Then her father calls a helicopter from Dare Enterprises and she rides to Manhattan to find Percy Jackson.
While the company is not seen, it's mentioned that it's extremely inferior when compared to the Triumvirate Holdings and compared Dare Enterprises to a Lemonade Stand next to them.