Maybe they are getting set early to sell once commercial flow rates are confirmed. I have noticed with some other companies that I converted options there was a lag time between the company processing my cheque and appearing in my account so maybe investors/traders were worried OEX wouldn't rush to process the conversion. In either case the converting of options is a good sign to keep all the financial side of things ticking over.
OEX Price at posting:
18.0¢ Sentiment: Buy Disclosure: Held