Inflation risk

Why nearly all stocks have negative exposure to unexpected change in the inflation rate, as their returns decline with positive surprises in inflation?

According to the bond yield plus risk premium method, ri =YTM on the company’s long-term debt + Risk premium, where YTM on the company’s long-term debt = real YTM on the government long-term debt + expected inflation + risk premium. Therefore, as inflation rate increases, stock return should also increase, right? Why the above statement says return will decrease?

You’re confusing the required return on common equity with the expected return on common equity.

If inflation increases, the required return on common equity will increase; the expected return may go up. go down, or remain unchanged.

Thank you. But could you please explain the reason why nearly all stocks have negative exposure to unexpected change in the inflation rate, as their returns decline with positive surprises in inflation? Thank you!