Anbeeld's Stockpile Economy aka ASE is a mod that implements a stockpile system in Victoria 3. The goal is to make it feel like a natural, useful and important part of the game that fits well into its market design. It has a friendly UI and helpful tooltips, can be used by both players and AI countries and is optimized to impact performance as little as possible.
The mod allows to set Price Targets for all market goods individually.
The Stockpile will buy them when the price is below Saving target and sell when it's above Spending target.
Saving costs money for the government, while Spending means getting the money into the country's treasury.