The death of former Federal Reserve Chairman Alan Greenspan at 100 has revived questions about the durability of the market doctrine bearing his name. For decades, investors operated under the assumption that the central bank would intervene to cushion stock market declines, a policy framework that became known as the Fed Put.

Greenspan first established this implicit guarantee during his tenure from 1987 to 2006, responding to market turmoil with aggressive monetary easing. The strategy treated equity market stability as essential to broader economic objectives, suggesting that falling stock prices could undermine the Fed's monetary policy goals. This approach fundamentally altered investor expectations about central bank intervention.

Now, with inflation resurging and the Fed pivoting toward tighter policy, markets are questioning whether that safety net still exists. The central bank's focus has shifted from backstopping asset prices to combating rising prices, leaving investors to wonder if the implicit guarantee has been permanently withdrawn.

The debate centers on whether the Fed Put created moral hazard or provided necessary stability during crisis periods. As monetary policy priorities evolve, investors face a new reality where central bank support for equity markets may no longer be automatic.