It is always good to be looking out for any suspicious activity...

It is always good to be looking out for any suspicious activity when one is an investor and/or trader in ASX-listed stocks, and one reason that I read HotCopper postings is that its contributors (you guys and gals) bring a lot of awareness, knowledge, "life-experience" and critical thinking to their contributions.
That said, there is nothing suspicious about this "substantial shareholder" notice.
DOW has 672Million shares on issue.
So the "now-ceased-to-be-substantial shareholder" T.RowePrice had about 5% of those, ie 33.6Million shares.
It has now told us that between 1 Nov 22 and 6 Dec 22 it bought about 65 thousand shares and sold about 162 thousand shares, including the sale of 149 thousand on 6 Dec.
Its net sales of about 97 thousand shares (+65 minus 162) represents only 0.3% of its holding.
Nothing to see here - Actually!
Of course, as it is now under 5%, T.RowePrice no longer has to report its portfolio sales (and so could have sold more on the 7th Dec - total sales on ASX were 4M that day, but that would still leave it with the vast majority of its holding.
T.RowePrice is hurting as much as we are - the $1.20 sp drop will have cost it around $40M.
But it is not for them that I have sympathy.
GLTH - we will need it!