When Kudra Falla-Ricketts, 16, sent an email on April Fools' Day she did not expect the hoax to attract so much attention.
The teen is being investigated by the Australian Securities and Investments Commission (ASIC) after she sent a fake press release to journalists claiming a local gas drilling site would be shut down.
But exploration company Metgasco's CEO was not amused, Fairfax reports.
Peter Henderson said the effect of the Lismore teen's email could have been "devastating" for shareholders.
The company quickly went into damage control, dismissing the hoax with a statement: "There is no substance to the hoax media release. Metgasco intends to continues its conventional and unconventional gas exploration and development activities."
False or misleading statements can attract a maximum penalty of 10 years in jail, a $765,000 fine, under corporations law.
Another NSW environmentalist, Jonathan Moylan, was charged with issuing a hoax press release last year, that allegedly wiped hundreds of millions of dollars off the value of Whitehaven Coal.
The 25-year-old allegedly sent a press release to the media claiming the ANZ Bank withdrew a $1.2 billion loan from Whitehaven's open cut coal mine.
Moylan has been backed by groups who claim the mining company plans to destroy koala habitats in in north-western NSW and force farmers off their land.
Rick Laird traveled to Sydney in support of Moylan last year and said most of his family-owned property would be destroyed by Whitehaven's exploration plans.
"We've been fighting these mines for years, and people are finally starting to hear about it," he said in a statement. "If these mines go ahead, it's the end of our livelihoods.
"We won't be able to farm the land and we worry about the impact of coal dust on our health."