Here comes the Fed statement ...

The Federal Reserve is set to release a statement announcing a major policy shift at 2 p.m. ET.

Economists don't expect another increase to the Fed's benchmark interest rate. Instead, the Fed is expected to say that it will soon start trimming the $4.5 trillion balance sheet it built up after the recession.

The Fed bought that much, in Treasurys and mortgage-backed securities, as part of its so-called quantitative easing process to push down borrowing costs.

But with the economy back on its feet, that emergency measure is no longer needed. The Fed began the process of tapering its purchases in 2013 and now wants to actively get rid of the bonds it owns. To do this, it would first stop reinvesting $4 billion of its mortgage securities and $6 billion of the Treasurys it owns. Then, it would raise these limits every quarter until they hit $20 billion a month in mortgages and $30 billion in Treasurys.

This process, alongside interest-rate increases, should put the Fed's policy more in line with an economy that's in an expansion.

The Fed wants this to be as uneventful as possible to Americans on and off Wall Street. One reason for that is that quantitative easing improved investors' appetite for risky financial assets.

"If they begin to let the balance sheet roll off in an aggressive way, that's taking money out of the system, and that would be negative for equities, said Byron Wien, the vice chairman of Blackstone's private wealth solutions group.

"I think they're going to go slow, so I'm not too worried about it. But you never know."

Fed Chair Janet Yellen is set to hold a press conference at 2:30 p.m. ET to explain the decision.

More to come ...