A 26-year-old Duke University graduate has raised another $2.1 million for her privately held energy drink company, according to a Securities and Exchange Commission filing.

MATI Energy sold $2.1 million to 19 investors, with $61,767 remaining to be sold. It has now raised $4.3 million in the last two years.

The form was filed Aug. 16.

Chief Executive Officer Tatiana Birgisson began brewing in her dorm room at Duke to stay productive through a bout of depression and later began bottling the tea and selling it to neighbors.

Backers, including AOL co-founder Steve Case, turned onto Birgisson’s product after she won a Google Demo Day pitch competition in Silicon Valley in 2015. Birgisson, who is half Icelandic and half Venezuelan, was one of four women founders to present at the competition.

MATI is now the best-selling energy drink in stores throughout the Southeastern U.S. It is sold in Whole Foods, Kroger and Costco. The manufacturer uses Guayusa, the second most-caffeinated plant in the world behind coffee. Its drinks have more caffeine than Red Bull.

MATI produces about 1 million cans per month.

The company claimed a Rule 506 (b) exemption. Companies relying on the Rule 506 exemption do not have to register their offering of securities with the SEC, but they must file what’s known as a Form D electronically with the SEC after they first sell their securities.

MATI sold $1.1 million to three investors, with the date of first sale June 8, 2015. It was amended on March 3, 2016 to $1.2 million sold to five investors.

It was amended on May 5, 2016 to $1 million sold to six investors.

Read the latest filing at:

https://www.sec.gov/Archives/edgar/data/1649456/000164945616000007/xslFormDX01/primary_doc.xml

Note: This story is from the North Carolina Business News Wire, a service of UNC-Chapel Hill’s School of Media and Journalism