A stock is in play when its whole group is moving and it is leading the group. The fastest way to find one is to start from the sector, not the ticker: see which of the 30 sector baskets is ranking up right now, check that most of its names are green, then open the basket and look at who is driving it. That takes under a minute on the free board, and it is the same routine every session.
On August 7 the Rare Earth basket was up 8.5% and ranked first of 30 on the free grid during the session, with every name in the basket green. The headline that explained the move ran the next day. Some members watch for exactly that shape: a small basket, full breadth, a fast climb up the rank.
No. The sector rank is the screener and the basket is the shortlist. A screener sorts thousands of tickers by one number; the board sorts thirty groups by how the whole group is moving, then hands you the names.
Yes. The baskets rank on pre-market prints from the first trade, so the groups in play are visible before the bell.
Then it is one name, not a group. Breadth is shown next to every rank so that case is obvious at a glance. Many members skip it or treat it as a single-name event.
No. In play means the group is moving and the name is leading it. Whether to trade it, how, and with what risk is a separate decision that this site does not make for anyone.