Strange idea that a collection of goodies can have a memory. When you see pebbles on a beach, they don't look as if they have a memory. Yet I don't mean this in some sort of strange philosophical way: I believe stocks really have a memory, in the sense that a future change is already embedded in the stock before the future arrives. This can be the direction of the change, or the intensity, or the force.
Maybe this becomes more easy to understand if you include some thermo: When I did not know the answers to a thermodynamica question as a student, I just filled in: "because then the system moves tot the lowest energy level", and that is still the best answer to many questions about why things are happening.
The same is true for stocks with a memory: the stocks know there is a lower energy level and they would like to go there. A bucket full of marbles on a hill top that has just been toppled has a memory: the markbles "remember" that they will start rolling downhill. A bank account remembers it can deplete, so a credit card is burning in your pocket. When you start a holiday game with a full bank account, you know it is going to go down. A country full of youngsters knows it can expect revolution. A city full of hooligans knows it will see riots and drunkeness.
More practically, if you are the manager of a warehouse with a certain inventory and your boss wants you to increase the inventory towards a desired level, ordering new products and going to the desired inventory is like going to a lower energy level. In this sense the inventory had a memory of where it would want to be. If you have ordered a new gadget and it is being flown to your doorstep by a drone, the pipeline of goods in transit (also a stock) has a memory of where it is going.
An ocean full of warm water has a memory in the sense that the huricanes are already in the process of becoming. A class full of children has a memory of creating chaos. A chimney that has not been cleaned for a long time will ignite when the conditions are right. A car moving at a certain fixed speed has a memory in the sense that it will continue to do so untill it is stopped. So inertia is a form of memory. Kinetic energy is a memory property of a stock (e.g. the car). Potential energy is a memory. And a banking account has potential energy. A warehouse has the potential to order replenishments. An empty stomage has the potential to be filled by eating.
Stocks have much more memory than flows. Flows stop flowing immediately when stopped. When eatign stops the flow stops. But the stomage can still be half-empty, so it remembers that more eating should be done.
So stocks have a memory.