From the IHUB trades page, I'm seeing that the trades at 21c totaled only 42,500 shares, and of that 10,000 was a Form T trade (after hours). The trades at 21c started at 3:59:46 (i.e., 14 seconds before the close).
I agree with the posters suggesting that it might be to make the percentage gain larger on the day someone announces a pick. Or it might be someone wishing they'd bought more (or sold fewer) and trying to mess with the chart.
Whatever. Silly games.