speculators; speculative investors
Refers to market participants who trade based on price movements rather than long-term fundamentals. Often used in financial news to describe the forces behind short-term market moves.
Stock prices plunged on selling by speculators.
Speculative investors are active in the currency market.
Compound of 投機 (speculation) and 筋 (line, channel, or group). 筋 here indicates a group or faction with a particular interest, as in 金融筋 (financial circles).