Reason for sell off?

From the annual report.......
'Overall, FY2016 has been a year mixed with pleasing operational and financial success however, marked with sadness following the passing of the Company’s former Chief Executive Officer, Seth Brown, in April 2016. Gary Pearson was promoted to the position of Chief Executive Officer in October 2015, having been the Chief Operating Officer and together with his team, delivered a strong financial result and consolidated the foundations for future earnings growth.'

Could the selloff due to the estate of Mr Seth Brown liquidating its assets which might have consists of shares in ADA?
Does anyone know the amount of shares he might hold? I am just wondering why a fair bit of volume of shares are being traded.