noun
A financial market condition where prices are rising or expected to rise, characterized by investor optimism.
現在の強気市場はいつまで続くのだろうか。
I wonder how long the current bull market will last.
The opposite: a bear market where prices are falling and pessimism prevails.
Compound of 強気 (bullish, confident) and 市場 (market). The term is a direct translation of the English 'bull market'.