彼は為替市場で投機的な取引を行った。
Kare wa kawaseshijou de toukitekina torihiki o okonatta.
He conducted speculative transactions in the foreign exchange market.
不動産への過度な投機は市場の不安定化を招く。
Fudousan e no kadona touki wa shijou no fuanteika o maneku.
Excessive speculation in real estate leads to market instability.