The phrase "bullish bias" means having a positive outlook or optimistic attitude towards something, particularly in the context of financial markets. It suggests a belief that prices or values will increase in the future. Full definition
Bull markets have a natural bullish bias, so picking tops is a lot harder than picking bottoms. (bullmarkets.co)
The stock market is different from forex and commodities: it has a natural long term bullish bias. (bullmarkets.co)
Unfortunately for them, the stock market has a very strong bullish bias in a bull market, which means that they end up missing out on a big chunk of the bull market. (bullmarkets.co)