You need to look into the obligations of a reporting company. You either file or withdraw if you do not you are taking the risk of being suspended and or revoked. The SEC has been taking it very seriously in the past couple years. They have taken out hundreds of companies for not filing and are still going. It is a violation of the securities act (section 13) to not file if you are a reporting company. Considering the SEC in their correspondence has told them to file the 10Ks for the missing period it is not a good sign.
GRNO is an asset to this country's environment. That should not be overlooked.
For my money they could say "Buh-bye" to the SEC and FINRA. Canada seems to be a safe haven for US stocks trying to escape the manipulation of Wall Street.
Until the government realizes that cleaning up Wall Street is a do or die issue this market is a sham.