Hey folks, This is a question I admit I have been too ashamed to ask for a long time now. I've graduated with a master's degree with a GPA of 3.8 and have started a PhD in Economics now and this simple question still eludes me. I feel too ashamed to ask any of my colleagues so please can someone kindly help me?

Say a company emitts stocks to the market. The first time they get bought by people off the company (or the underwriting investment bank, I think) for a decreed price. Okay, so far so good. Now imagine I want to buy a stock of a certain company that is not currently issuing new stocks. I have to buy it at its current price, i.e. the course of this stock, right? For me to be able to buy it, I have to buy an existing stock from someone else who currently owns it. So in other words, at the current price, there is someone willing to buy it and someone willing to sell it.

How does that drive up the price of the stock? In economics, we're always told "buying the stock raises the price of the stock", and conversely, "selling the stock lowers the price". But how can actual transactions at the current price change the price?

Perhaps this story is rather about buying (selling) at a higher (lower) price than is currently in the market, i.e. moving towards equilibrium from an excess demand (supply) to market equilibrium. That I can understand. But how does it work at the actual price? Can someone explain this, please?