Ever since stocks started falling last month, many investors have wondered when the Federal Reserve might step in to provide additional support to the economy. This morning, investors discovered that they'd gotten the support they'd expected -- but from an unexpected source. Rather than the Fed, it was the People's Bank of China that stepped in, cutting its deposit and lending rates by a quarter-percent for the first time since 2008. The surprise sent stocks soaring, although less enthusiastic comments from Fed Chairman Ben Bernanke cut the gains in the Dow Jones Industrials (INDEX: ^DJI) to 66 points just after 10:45 a.m. EDT, and the Nasdaq Composite (INDEX: ^IXIC) actually lost ground. Nobel laureate Joseph Stiglitz joined George Soros in predicting a big blow-up in Europe, citing a failure of banks and governments there to take necessary action.

Caterpillar (NYSE: CAT) posted the biggest gains in the Dow early with an almost-2% rise, as a China-led economic stimulus could have a big impact on its construction and mining equipment business in the emerging-market nation. Yet it's important to remember that the whole reason why China has had to cut interest rates is its belief that growth is slowing, which suggests that Caterpillar's potential recovery won't happen overnight.

United Technologies (NYSE: UTX) also continued its winning ways from yesterday, rising almost 2%. The company needs economic strength to bolster its business both in the U.S. and abroad, so Chinese stimulus by itself won't be enough. Bernanke's comments may well signal that United Tech and its peers shouldn't count too much on monetary stimulus in the future.

Finally, Pfizer (NYSE: PFE) rose about three-quarters of a percent after announcing that it would spin off its animal health unit through an initial public offering, with full divestiture expected in mid-2013. The new company will be named Zoetis and should have global exposure, with the unit's 2011 sales weighing in at $4.2 billion. The move follows Pfizer's sale of its infant nutrition business and is part of Pfizer's previously announced plan to refocus its efforts on its core drug business.

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