Wall Street is an actual street in NYC, right the heart of the Big Apple's financial district.

When people talk about Wall Street, though, they're not talking about the place you can street view on Google Maps. They use it as a way to describe important investors and big business. So when they say "Wall Street is optimistic about Apple stock," they're not personifying pavement; they're saying that big financial movers and shakers in this country are optimistic about Apple stock.

It's metonymy, people.

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