I was unable to establish why that occurred when investigating...

I was unable to establish why that occurred when investigating SSM prior to my recent purchase. It seemed to occur almost immediately after the publishing of the HY19 accounts. My assessment of the accounts was that there was no justification for the selloff but of course after that Covid-19 became an obvious threat to the economy. IMO sometimes investors have very high expectations of the company and when the results do not match their assessment they sell off and take their profit. I have looked for institutional selling but there is no evidence of that they seem to be holding and the directors are also regular on market buyers. So I have put it down to a number of investors with either too high expectations or those waiting for results to boost the SP with plans to sell afterwards anyway. One other trend which often occurs is the rise in price before results due to expectation of a good result and the selloff afterwards when the traders find it did not bounce upwards. Maybe some other holders are closer to the company and may be able to enlighten you and me too for that matter.