1Speculation: buying or selling assets (e.g., stocks, commodities) to profit from expected price changes; a high-risk, often short-term activity.
彼は短期的な投機で大きな利益を上げた。
He made large profits from short-term speculation.
不安定な相場では過度の投機は危険だ。
Excessive speculation is dangerous in an unstable market.
投機的な買いがバブルを膨らませたと指摘された。
It was pointed out that speculative buying inflated the bubble.