WASHINGTON — Staring at spreading financial dangers, the Federal Reserve announced a rescue package yesterday that pours as much as $200 billion into banks and investment houses and allows them to put up risky home-loan packages as collateral.

Wall Street rebounded with its biggest rally since 2002 — and hoped the Fed had even more cards to play.

The Federal Reserve's maneuver, coordinated with central banks overseas, was its latest effort to stem the global credit crisis and severe housing woes that threaten to bury the United States in its first recession since 2001.

Fed Chairman Ben Bernanke and his colleagues have been stretching for new and imaginative ways to confront the situation.

They are hoping to bring relief where it is sorely needed: in the market for mortgage securities. Home loan financing has become much harder to get as nervous lenders have hunkered down.

"It is a highly significant move. The Fed is innovating in a way that is going to push liquidity directly into the mortgage markets, where it is most needed," said David Jones, president of DJM Advisors.

By allowing financial institutions to put up mortgage-backed securities — for which there's little market appetite — in return for safe securities that are in high demand, the Fed hopes to take pressure off financial companies and make them more inclined to lend to individuals and to businesses.

If the effort works, it should in time help to keep home loan rates down, especially on those backed by Fannie Mae and Freddie Mac, which are the few remaining sources of mortgage financing as credit has increasingly dried up elsewhere, said Mark Zandi, chief economist at Moody's www.Economy.com.