Think of a price as something that normally moves: it drifts up when things are scarce, and down when a rival opens across the street. Now picture a hand reaching in and holding it still. That is the fix in this word - not repairing anything, but pinning a number in place so the market can no longer push it. The only question left is whose hand it is, and whether everyone can see it.
Two branches
賣方私下按住的手
按住價格的是本來該互相競爭的公司，而且是暗中做的。
noun · C1
A secret agreement between companies that are supposed to be competing, in which they all keep their prices at the same high level so that buyers cannot find a cheaper one. In most countries this is against the law.
聯合哄抬價格
政府公開按住的手
同樣把價格釘住，但按的是政府，而且寫成人人看得到的規定。
noun · C1
A system in which the government, rather than the market, decides what things may be sold for.
政府定價