I try to not let information (market reports, economic news etc.) get into the BB process, but I occasionally take the weekend FT. As it happens, I don't think that BB should work better or worse in a bull or bear market, but it's possible we can see what has been going on with the recent poor performance of the strategy.
Over the last 2 weeks, the US markets have shown 'growing concerns about the sluggish pace of US recovery. Outperformance by defensive stocks highlighted the market's nervous mood.' This week the US markets turned 'increasingly volatile', still concerned over the recovery that might not be, plus eurozone sovereign debt issues. These concerns and similar rotational activity was reflected in the FTSE100.
The key here is fear - if markets were going consistently upwards, I am sure BB would be working better, not because of the points total being added, but becasue there would be a consensus on direction. At present, there is no consensus - some stocks are going up, some down, sdome ppeople are buying at lows, others are panic-selling. The indices are overall falling, but it's the volatility that's the key, not the total points fall. I'm saying a 500pt FTSE100 uptrend is better for BB than a 1,000pts FTSE100 downtrend. Also, that it's possible some bear markets might be broad consensus-driven and actually a very good platform for BB - but not the FTSE right now.
Also from today's FT, it seems a rescue for Greece is agreed which will not fracture the German banks and government and will not split Greece from the eurozone. This might hail a period of reduced volatility after the weekend............, I hope.