What does the quantity of money have a stable relationship with?

In the standard theory, demand for money has a stable relationship with income (with nominal GDP), it is demand for transaction money. At equilibrium in the medium term, in this standard theory, an increase in the money supply therefore increases prices, which rebalances money supply and demand. But this can no longer be seen today, which means that demand for money has a stable relationship with variables other than income. Possibilities include: The value of assets: equities, real estate. Observation of facts clearly shows a link between the money supply and market capitalisation or the value of real estate assets; The value of outstanding bonds, which rises due to the fall in long-term interest rates; we see a link between the value of bonds and the money supply. This shows that an increase in the money supply does not increase prices of goods and services, but probably increases the prices of equities, real estate and bonds .