Investors/traders usually buy in on a "solid rumor" and sell into the news.
Someone knows that something BIG has been done, and is gathering shares.
Case in point, NIII on L2. They were gobbling up shares all day yesterday.
During the last run, we saw MERC as a new MM. Sometimes when a new MM logs on, and is very active, then it could be a sign. This is another reason folks here should have real time L2, with MM ids.