Livermore, I have heard of this as being called the Big Ben effect. I think it would be useful to get as much trading history as possible before deciding whether or not it is a tradable observation. There was a period when I recorded the daily charts thinking that the Big Ben effect could be exploited. I started observing this after watching a few days of price action just like we had today (cable started dropping just before 7:00 and continued to move lower). Alas, my stats didn't hold up for the duration and I gave up on the exercise. Maybe I didn't have enough observations. On average the idea may have some worth. I would say it is a different to other calendar effects that have been observed because it represents a time when more traders are definitively entering the market and establishing new positions. When I was looking at this stuff, the NY open and Tokyo open seemed to have less of an impact. It makes sense because the boost in liquidity going from the Tokyo session to the London session is likley the greatest in % terms.
We also got a big move bang on midnight last night as the mkts opened up for trading, which sometimes happens.
