Ann: ASX Notice, page-16

They confirmed today that its the shares held on the vesting date (22nd March 2018) that determine the amount of option you received, to a maximum of shares subscribed to in the IPO.

From email:
"It is worth highlighting that any initial IPO investors who may have sold part or all their IPO stock will still be eligible to receive their loyalty options if they hold shares on the vesting date. For example, the initial investor with 10,000 shares who may have sold 5,000 of their shares will be entitled to 5,000 options on 22 March if they make no further sales or purchases. If the increase their holding back to their initial IPO investment of 10,000 shares by the vesting date they will be entitled to 10,000 options. If they increased their investment to 15,000 shares at the vesting, they would still only be eligible to receive 10,000 options, being the 1 for 1 rights based on the stock they acquired in the IPO."