Stan Kroenke, as far as soccer team owners go, is fairly...I guess not uncontroversial, but when you compare him to the Glazers, Roman Abramovich, or Randy Lerner, he looks like a pretty solid guy that you'd want as your team's owner, really. Today, Stan increased his ownership stake in the club, buying 23 additional shares for £368,000 (£18,400/share), bringing his total ownership stake to 67.05%.
I don't think this is a precursor to him buying out Red & White's 30.05%; the 2.9% of shares not owned by those two parties are owned by a collection of people, minority owners and ex-players and the like. The Arsenal Supporters' Trust also owns three shares.
Most likely, this was one of those "random" shareholders cashing in a bit; maybe they needed a new car, or wanted a nice vacation or to pay their kid's college tuition or something. It's not major news, for sure, and it doesn't change anything at all as far as how the club operates, but it's a thing to talk about, so here we are, talking about it.