Ann: Notice of 2019 Annual General Meeting and Annual Report, page-6

And to answer your actual questions:

It may not mean they consider TAFTA to have great chances, but even good chances could convince them to do a buy-back, if they feel that the cash balance has spare capacity, and that their risk adjusted valuation of the shares shows them to be worth eg. $0.60+.


Why would people sell? The same reasons people today are selling for $0.43, but the buy-back could mean buying back shares from $0.43-0.50, so it would convince some further shareholders to sell (the ones who wouldn't accept $0.43, but would accept $0.48).