What can we predict will decrease when supply increases and demand decreases?

When supply increases and demand decreases simultaneously, the most predictable outcome is a decrease in price.

In economic theory, an increase in supply means that sellers are offering more of a product or service at each price level. This surge in availability tends to put downward pressure on prices, as there’s more of the good available than before. Conversely, a decrease in demand signifies that fewer consumers are willing or able to purchase the good at that price level. When demand decreases, sellers may find it necessary to lower prices further to entice the remaining consumers to buy their extra inventory.

Thus, with both conditions in play—an increase in supply and a decrease in demand—the market becomes characterized by excess supply relative to demand, leading to a reduction in price as suppliers try to clear their surplus. This makes it clear why the decrease in price is the correct forecast when these two dynamics are observed in the market.