"In this climate, it's what the buyers believe and where there's smoke, there's fire". What does this mean?

Question

So I am currently watching Wall Street: Money Never Sleeps and I heard this statement:

In this climate, it's what the buyers believe and where there's smoke, there's fire.

What does it mean?

Answer 1

He's talking about "Market Panic". If a lot of people start dumping stock, other brokers assume someone has some inside knowledge and they will start dumping stock too. Works the same way in reverse; if a lot of people start buying, others will buy too assuming someone knows something.

In those first few cases, they're the "smoke". Once it takes off, that's the "fire".

And, when you build a campfire, if you have some smoke coming out of it then there's a good chance you can get a fire going. Hence the saying, "Where there's smoke, there's fire".