Sony CEO Just Sold over Half His Stock

My gut reaction to stuff like this is that it's a coincidence. Looking at the insider trading on Sony, it does seem odd that a company that size only has trades from the last 3 months. I was expecting to see some history of this being a yearly thing. That said, I have no idea what the culture around holding/selling company stock is in Japan.

https://www.marketbeat.com/stocks/NYSE/SONY/insider-trades/