What Is the Biggest Driver of Stock Prices? The Real Answer

If you ask most investors, they'll say earnings. But after a decade of trading both my own money and institutional funds, I can tell you that's only half true. The biggest driver of stock prices—especially in the time frame most people actually care about—is liquidity and positioning. Let me explain.

Earnings Are the Baseline, but Don’t Stop There

Over the long run, stock prices follow earnings per share growth. That’s not a controversial statement. You can pull up any chart of the S&P 500 alongside aggregate corporate profits and they move together like two old friends. I did this exercise years ago when I was starting out, and the correlation is striking. But you have to zoom out to decades to see that relationship clearly.

Here's what they don't teach you in school: in the short to medium term, earnings are often just an excuse. I remember buying shares of a company that beat earnings by 10% and raised guidance. The stock still fell 7% that afternoon. Why? Because the market had already priced in that beat, and more importantly, the tide of liquidity was going out. It was a classic case where good news didn’t matter because there was no new money coming in.

So yes, earnings set the baseline. They tell you what a business is worth in a vacuum. But they don't tell you what the crowd is willing to pay for it on a given Tuesday. I’ve seen undervalued stocks sit flat for months while overvalued momentum names keep ripping higher. Earnings are the map, but they’re not the road.

What Actually Drives Stock Prices in the Short Term?

When I look at a price chart, I'm not asking if earnings are good. I'm asking three different questions. These questions have guided my trading for years, and they’ve saved me from a lot of heartbreak.

1. Is the central bank adding or draining liquidity?

Money supply matters. When the Fed (or any major central bank) is buying assets or keeping rates low, that extra cash has to flow somewhere. A lot of it lands in stocks. You can see it in the data: periods of QE (quantitative easing) almost always produce rising equity markets, regardless of what earnings are doing. Conversely, when the Fed is shrinking its balance sheet or hiking rates, stocks tend to struggle even when profits are solid. I remember checking the Fed’s balance sheet statement every week during one particularly volatile period. The market was completely disconnected from earnings news. The only thing that moved stocks was a change in the size of the balance sheet.

For example, if you see a market rally on heavy volume while the Fed is actively buying mortgages and Treasuries, you can be pretty sure that rally is driven by liquidity, not by a sudden improvement in corporate fundamentals. That’s a crucial distinction. If the driver is liquidity, it can reverse as soon as the central bank blinks.

2. What is the overall sentiment?

Fear and greed drive real flows. I’ve seen weeks where the only news was good, yet the market fell because everyone was already max long. Sentiment indicators like the put/call ratio, the VIX, and surveys of consumer confidence give you a decent read on whether there’s still fuel in the tank. When the put/call ratio gets extremely low, it means everyone is buying calls and no one is hedged. The market is fragile. A tiny piece of bad news can trigger a cascade of selling because there’s no one left to buy. On the flip side, a high put/call ratio means there’s a lot of fear, which often marks a bottom. I don’t use sentiment as a timing tool, but I use it as a reality check.

3. Where is the positioning?

This is the sleeper. If every hedge fund is already heavy in tech stocks, then good news doesn't matter because there's no one left to buy. You're just waiting for the first seller to start the avalanche. Positioning data (like IMM net specs, CFTC reports, or even trading volume trends) tells you who’s already in the boat. I’ve been guilty of buying into a crowded trade myself. You hear about it from five different sources, so you assume it’s the right thing. But when everyone else is already in, you’re the last one in line. The only way you make money is if someone even later buys after you. That’s a losing game.

These three factors don’t act in isolation. They interact. For example, a central bank can inject liquidity, but if sentiment is already euphoric, the effect might be muted. That’s why you have to watch all three together.

The Real Biggest Driver: Liquidity and Positioning

If I had to pick just one factor that explains most short-to-medium term price moves, it's liquidity. Not earnings, not news, not even fundamentals. The reason is simple: liquidity is the fuel. Without new money flowing in, a stock can’t go up even if it’s undervalued. With that flood of cash, even junk stocks rise. I’ve traded in both conditions, and I can tell you: a rising tide lifts all boats, but a falling tide reveals who’s swimming naked.

Think back to the market bottom during the global financial crisis. Corporate earnings were horrible, yet stocks eventually bottomed and started a massive rally. What turned it around? Central banks flooded the system with liquidity. It wasn't an earnings recovery; it was a liquidity event. That pattern repeats itself every time. Just look at any major market panic in the past two decades. The mechanics are always the same: after the crash, the central bank steps in, credit spreads narrow, and stocks rebound. The companies don’t change overnight. The price action is entirely driven by the availability of money.

Let me give you a concrete example from my own trading. A few years back, I held a mid-cap tech stock. The company announced record revenue and boosted guidance. My fundamental analysis said it was worth at least 15% more. But the price barely moved. Over the next week, it dropped 5%. Meanwhile, the broader market was flat. What was going on? I checked the Federal Reserve's balance sheet—it was shrinking. The market was in a liquidity withdrawal, and no amount of good earnings could overcome that. I sold the stock, and I’m glad I did. It went on to underperform for months.

Positioning is the second half of the equation. If everyone is already long, then all the liquidity in the world can’t push prices higher because there are no new buyers—unless those buyers are forced into the market by fear of missing out. That’s why you see explosive moves at the end of cycles: a small amount of new money enters and triggers a short squeeze or a melt-up. I’ve watched it happen repeatedly. The final leg of a bull market is almost always a positioning squeeze, not a fundamental improvement.

This is the non-consensus view that most retail investors miss. They obsess over earnings calls, EPS beats, and guidance, while the real battle is happening in the liquidity channels and the order flow. Once you understand this, you stop fighting the tape and start reading the flows.

How Can You Use This Knowledge to Predict Stock Prices?

You don't need a Bloomberg terminal to see the big forces. Here's a practical checklist I use every week.

• Track the central bank’s balance sheet. The Fed publishes this data every Thursday. I look at the weekly change, and if it’s positive for six consecutive weeks, I know the tide is rising. If it’s been shrinking for a month, I reduce my risk. It’s not a perfect indicator, but it’s a powerful tailwind or headwind.
• Watch the yield curve. Inverted curves have a strong track record of predicting recessions and bear markets. I like to see the 10-year vs. 2-year spread as a guide. When it flips negative, I start building cash. I don’t dump everything at once, but I definitely stop buying.
• Read the positioning data. Free resources like the CFTC’s weekly Commitments of Traders report tell you where speculators are. When everyone is on one side, expect the opposite. It’s contrarian, but it works because the market rewards those who aren’t running with the herd.
• Use price action as a final filter. Even if earnings look great, if the stock breaks below key support on rising volume, something is saying the market knows more than your spreadsheet. I always wait for the chart to confirm my fundamental thesis. If it doesn’t, I step aside.

I also like to look at margin debt. When investors are borrowing heavily to buy stocks, that’s a sign of excessive optimism and reduced buying power. It’s not a timing tool, but it tells you how much fuel is left in the fire. When margin debt is at record highs, I get nervous. It means a lot of buying has already been done with borrowed money, and that debt has to be repaid eventually.

One more tip: pay attention to the funding markets. If you see repo rates spike or credit spreads widen, that’s a red flag. It means liquidity is tightening behind the scenes. I’ve caught several downdrafts early just by watching these obscure rates.

Common Mistakes That Keep Investors from Seeing the Real Driver

Here are the three most common mistakes I see from clients and readers. Avoiding these will put you ahead of most retail traders.

Mistake #1: Mistaking news headlines for the cause. News is just a catalyst. The real driver is how the liquidity and positioning backdrop reacts to that news. A bad jobs report can be good if it means the Fed will cut rates. Stop reading the headline and start reading the tick. I can’t tell you how many times I’ve seen a stock gap up on a “great” earnings report, then fade all day because the market realized the numbers were inflated by one-time gains.

Mistake #2: Using a long-term lens for short-term trades. I get it, you bought a stock because you like the business. But if your time horizon is 3 weeks, then earnings quality doesn’t matter as much as whether there’s a seller up the ladder. Match your strategy to your horizon. If you’re a swing trader, you need to think like a swing trader. That means focusing on momentum, volume, and the liquidity environment, not just the P/E ratio.

Mistake #3: Ignoring the crowded trade. When every TikTok financial guru is telling you to buy the same tech stock, you’re likely late. The trade is already packed. You want to be where the future buying power is, not where it has already been spent. I remember when everyone was piling into a certain EV stock. It had great fundamentals, but the position was overly crowded. When sentiment shifted, the stock dropped 50% in two weeks. The long thesis was intact, but the trade was broken.

Frequently Asked Questions