Actually, one already exists, but very little is written there. I think the title is a bit misleading, but as I understand it, it’s also allowed to announce purchases/sales there, and pretty much everything else related to trading.
https://keskustelut.inderes.fi/t/treidaus-liveseuranta/4578
E: Personally, I think all buys/sells should just go into the same thread, regardless of holding period or reasons for buying. Otherwise, soon we’ll need threads for “I bought from Finland/Abroad/USA/on Monday from the dip/on Tuesday with a fur hat on/on Wednesday drunk and for a laugh…”