ENVIRONMENTAL activist Jonathan Moylan has narrowly avoided jail for instigating a hoax that temporarily wiped more than $300 million off a coal company's sharemarket value.

The 26-year-old, of Newcastle, was sentenced in the Supreme Court in Sydney to 20 months' jail wholly suspended on the condition he be of good behaviour for two years.

In January last year while living at a protest camp in the Leard State Forest, near Boggabri, Moylan used a laptop to sent out a fake media release under an ANZ letterhead.

The release claimed the bank was withdrawing a $1.2 billion loan facility to Whitehaven Coal to fund construction of its controversial $767 million Maules Creek coalmine.

Several media outlets published the elaborate hoax as fact, prompting panicked investors to dump Whitehaven Coal shares before trading was eventually suspended.

Several Maules Creek residents were among a throng of Moylan supporters at the court this afternoon to hear Justice David Davies hand down his verdict.

Justice Davies told the court that Moylan's guilty plea, entered in May, had saved him from a custodial sentence.

For the full story, including reaction from Maules Creek residents to the sentence, see tomorrow's edition of The Leader.