speculative battle; large-scale speculative go-around
A stock market term referring to a situation where speculators (仕手) aggressively trade a particular stock, causing large price swings. Often used in the context of a group of speculators targeting a stock.
That stock is showing signs of a speculative battle.
I got caught up in a speculative go-around and lost a lot of money.
相場操縦 is a broader term for market manipulation, often illegal, whereas 仕手戦 can refer to legal (though aggressive) speculative activity.
Compound of 仕手 (して, 'speculator' or 'player') and 戦 (せん, 'battle' or 'war'). The term likely originated in Japanese stock market jargon.