FILE PHOTO: A modified Tesla Model X drives into the tunnel entrance before an unveiling event for the Boring Co. Hawthorne test tunnel in Hawthorne, California, U.S., December 18, 2018. Robyn Beck/Pool via REUTERS

(Reuters) - Elon Musk’s Boring Co raised about $117 million in its latest round of funding from 20 unnamed investors after offering to sell about $120 million in equity, the company disclosed in a regulatory filing on Friday.

The company had raised $112.5 million in equity in April last year, with Musk investing 90% of the amount, as the company seeks to build underground tunnels for hyperloop transportation project. (reut.rs/2DIZwLJ)

Boring Co did not provide details on the funding.

Musk, who also leads electric-car maker Tesla Inc TSLA.O and rocket company SpaceX, has been seeking to revolutionize transportation by sending passengers packed into pods through an intercity system of giant, underground vacuum tubes known as the hyperloop.

In the past, Musk has sold Boring Co’s hats and flamethrowers to raise funds.

The company has completed its project Test Tunnel, located in Hawthorne, California, and other ongoing projects include the Chicago Express Loop and the Las Vegas Convention Center Loop. (bit.ly/2NenvXU)