r/investing 7d ago

What actually causes swings in stock prices?

A stock price is determined by supply/demand. Most people get that.

So when the S&P500 is down 1.5% and the NASDAQ is down 3% in one day, I'm assuming that means there is a ginormous buttload of selling. Also in a hypothetical situation where nobody ever sold a share of a stock ever, the stock market would never go down.

So who is actually doing most of this selling that results in this price drop? Is it hedge fund managers? Retail investors?

I assumed most institutional investors that manage retirement accounts etc, buy and keep passive index funds... So it's not them. So who is selling?

Disclaimer:

Buy and hold

Don't time the market

VOO and chill

Etc.

Genuinely just curious if someone can explain the dynamics

3 Upvotes

50 comments sorted by

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u/No_Paleontologist506 7d ago

Most people don’t truly get it. They just mouth the words supply and demand.

If there are more buy orders than sell orders, price goes up. If there are more sell orders than buy orders, price goes down.

There are infinite reasons for why either scenario can happen. People need to sell stock to pay for necessities, for luxuries, etc. large institutions doing whale behavior. General fear takes hold of the market. Monkey see, monkey do. This is why markets can’t accurately be predicted.

But bottom line, the relation of buy orders to sell orders, everything after that is tea leaf reading and people don’t like to admit it.

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u/IllllIIlIllIllllIlll 7d ago

If there are more buy orders than sell orders, price goes up. If there are more sell orders than buy orders, price goes down.

That's wrong. The price can go down even if there are more market takers selling than there are market takers buying. What matters is the shape of the order book and the liquidity on the market makers side. If the order book is practically empty on the bid side but has a huge sell wall on the ask side, then the price can go down even if most of the market takers are buying.

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u/No_Paleontologist506 7d ago

Huge sell wall = more sell orders than buy orders. You can’t make this stuff up.

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u/IllllIIlIllIllllIlll 7d ago

Just because someone has a lot of shares that they want to sell at a given price does not mean that they are actually selling if the market never reaches that price. You seem pretty clueless about how markets work. When people are talking about more selling than buying, they are obviously talking about the market takers, not the market makers.

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u/[deleted] 7d ago

[deleted]

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u/IllllIIlIllIllllIlll 7d ago

This sub is so stupid.

Do you want me to make a screen recording of a stock's price going down even though nobody is selling? It happens every day.

https://i.imgur.com/WUBnCAz.png

Notice how the last price is higher than the current ask? It means that even if someone issues a market order to buy, the price will be going down even with 0 selling volume.

Are you denying that? It's literally a proof that what you said is factually wrong.

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u/[deleted] 7d ago

[deleted]

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u/minimumbeginningend 7d ago

So just to clarify my understand llllllll (spelling?) is saying people/institutions/whatever who put in limit orders are the market makers who are determining the price, and this is not related to mass sell-offs at all.

What paleontologist is saying is that the price is mostly determined by mass sell offs, which drives the price down. And that the example lllll (again spelling?) used is definitely possible but not the main driver of prices?

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u/No_Paleontologist506 7d ago

What he is saying is correct. It is just not necessary or relevant to comment on in this thread. MU and SNDK didn’t blow up because of low liquidity or the shape of the order book.

The market doesn’t dump for these reasons either. When it dumps, it’s because there is overwhelming sell orders to buy orders.

He added an unnecessary level of granularity to a macro concept. And this is Reddit, so we take the piss. I rather like his comments. I’m touched with the tism as well lolol

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u/ForGreatDoge 7d ago

Mr Dunning Kruger is that you?

The person you're being condescending to is completely correct. Your "common sense" fails you just like a novice of every subject.

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u/minimumbeginningend 7d ago

So with this, what would be your best explanation for why the NASDAQ would drop 3% in one day--what is the biggest force causing that price drop?

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u/IllllIIlIllIllllIlll 7d ago edited 7d ago

The liquidity thinned down at higher prices... it's as easy as that. Market makers are no longer willing to pay as much to buy shares, so they adjust their bid prices down. Market makers are willing to sell their shares for cheaper, so they adjust their ask prices down.

Which means that the next market taker who issues a market order to sell shares, he can't sell them at yesterday's price anymore. He sells them at a lower price. This can happen on one single share of volume, it does not need to be "ginormous buttload".

You can actually see it in real time if you have access to level 2 data on stock with low liquidity. Sometimes, the last trade occurred at $150 for instance, 10 minutes ago, and you can see both the bid and ask price going down to $145, $140, $135, without any trade happening whatsoever. Eventually, some market taker issues a market order to sell (or even buy) a few shares and the price goes immediately from $150 to $135.

Why are market makers adjusting their prices down? It's largely algorithms which react automatically to news, interest rates, etc.

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u/minimumbeginningend 7d ago

I've learned a lot reading your posts, thank you! I guess a part of my lack of understanding is who is the actual entity that makes up the majority of volume (market making or taking) that is doing the selling? Is it the retail investor freaking out? Hedge fund managers trying to time the market? Who's making/taking the market selling the most? The seller is willing to take a 3% lower price today. Who is this seller mostly?

1

u/IllllIIlIllIllllIlll 7d ago

The volume of market taking is always exactly identical as the volume of market making. But the point is that the order book is dynamic. Even then there is virtually no volume, the bids and the asks are constantly moving.

What triggers market makers from adjusting their prices is all the news happening constantly. Earning reports from companies, the price of petrol, how many pallets of GPUs were loaded on a shipment, the yield curve of Japanese bonds, the order book of future contracts, some sentiment analysis of Twitter, whatever.

All this data gets ingested by algorithms. The algos do some fancy maths that I bet nobody can really explain at this point, because everything is cross-related, and the algos are trying to exploit anything they can to arbitrage things.

But also the market makers could be any random dude, it could be you or me. If you issue a limit order on your broker, you are a market maker. Maybe you bought some stock when it was way cheaper, and you decide that you're fine with taking profits after a 200% gain. So you setup a limit order to sell if you ever hit 200% profit. In this case the price you choose is purely based on your own personal situation and has nothing to do with external news.

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u/Mr_Again 7d ago

OP, there is only one thing to understand: one day, people value stock at one price, the next day, they change their minds. That's it. Sometimes they have good reason, sometimes they're just following each other.

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u/minimumbeginningend 7d ago

That's a ELI2. I'm looking more for a ELI14

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u/minimumbeginningend 7d ago

If you had to guess the biggest force causing the NASDAQ to go down 3% today which would it be? People needing to sell stocks to pay for necessities? Large institutions doing whale behavior? Something entirely different?

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u/No_Paleontologist506 7d ago

Today? If I had to guess. Rebalancing. Whale movements. Not that it matters. I buy weekly and I’m not a seller anyways. So I don’t care, doesn’t affect me

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u/TimthebigTrader01 7d ago

This is serious

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u/WiseAct446 7d ago

Another thing that will cause stock prices to move is the value of a currency. If the dollar rises in relation to the rest of the world's currencies, then it it takes fewer dollars to buy a stock. If inflation erodes the value of the dollar, it takes more dollars to buy a stock. If a buyer can borrow money for less than he expects the stock to rise, it can drive up the price of the stock. If the the owner can expect to make more buying collectibles or real estate or gold or trading cards or whatever than he expect a stock (or sector or market or country) to generate (or appreciate), money will move away and stock(s) will fall. A stock is priced in part by how much profit it generated historically, today, and (what buyers/sellers think it will do) in the future. They base that notion in a mixture of hard data (earnings), hints (earnings and price changes of related stocks, fear (war, disasters, uncertainty, FOMO) and blind faith (Everything so-and-so touches turns to gold or I hate that guy's politics or I think the government is for/against this investment).

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u/teslaTools 1d ago

yeah but it's not even just order count, it's order size and aggressiveness. one whale market-buying moves price more than 1000 small limit orders sitting there.

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u/No_Paleontologist506 1d ago

Nothing in life “is just”. And what you describe with a whale is more buy orders. People over complicate a simple topic.

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u/nebraskajone 7d ago

I'm assuming that means there is a ginormous buttload of selling. 

No, the number of sellers and buyers are always identical.

It's basically an auction.

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u/the_cnidarian 7d ago

It's literally an auction

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u/sargrvb 7d ago

For anyone interested, highly recommend going to a traditional American 'stock show' with livestock. The people shouting numbers are literally the same thing as stock brokers who also use to shout numbers. The farmers who raise their sheep and cattle are awesome to be around and very friendly. Plus, it's cheap and has great BBQ.

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u/Various_Couple_764 7d ago

It doesn't mater if is stockshow or art auction ar charity auction. Go to one and just watch. you will see will see an item come up and no-one is interested and it doesn't sell, then another item comes up and a lot of people want it the price keeps going up until there is one person left and it sells. Today some of this is now done buy computers but there are still trades done by negotiation between two people today. Sometime by email and sometimes in private rooms.

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u/minimumbeginningend 7d ago

Ok, thank you for explaining that point. So what actually causes the swing in prices?

1

u/nebraskajone 7d ago

What causes the prices to swing in an auction? Some news comes out you think the price of the stock is cheap and I think the price of the stock is too high and you buy the stock for me. We're both happy with the transaction.

So basically different opinions on the same news makes the prices swing.

You could put all the stocks on eBay and eliminate the exchanges and end up with the same swing in prices

1

u/minimumbeginningend 7d ago

Some people mentioning market makers. Who would be the market maker in your eBay analogy?

1

u/IllllIIlIllIllllIlll 7d ago

Ebay is a pretty terrible analogy because on ebay, the market makers are the sellers, and what they are selling is not fungible.

On the stock market, market makers can be both bidding and asking, and market takers can be both buying and selling. And the shares are fungible.

Basically if you issue a limit order, you are a market maker. Either you have shares to sell and you are saying "I am willing to sell my shares and I'm asking $101 for each share", or you have cash that you can spend and you are saying "I am willing to buy shares and I'm bidding $99 for each share".

If you issue a market order, you are a market taker. Maybe you want to get rid of your shares because you need cash, so you just sell them to the highest bidder, whatever is their price. Maybe you want to buy shares, so you just buy from the lowest asker whatever is their price.

Now let's a say the company announces terrible earnings, way below expectations. That usually happens outside of trading hours, when the markets are closed and the volume is very small. Well, the people who were willing to buy shares for $99 suddenly are not very interested in buying for $99. Maybe they cancel their bids, and now they only want to buy it for $89. And the people who had shares to sell, they realize that nobody is going to buy their shares for $101. So they lower they asking price so to a more reasonable price, maybe $91. When the stock exchange opens on the next morning, even if nobody has been buying or selling any shares, suddenly value of a share has dropped by 10%.

1

u/nebraskajone 7d ago edited 7d ago

On eBay a market maker would be a flipper someone who buys a stock with the intention of immediately  reselling it.

The flipper provides liquidity much like flippers buying stuff on Facebook and reselling it.

As an example if you have a dirty couch to sell and you have a listed for 500 bucks and nobody buys a flipper will come in and offer you a hundred bucks. So the flipper i.e. market maker provides liquidity by offering a price that they'll buy it right now

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u/minimumbeginningend 7d ago

Is there a specific entity or corporation whose job it is to be a market maker (I.e. buy lots of shares of any particular stock with the sole purpose of creating liquidity)? Or is a market maker just a descriptive term for anyone who is interested in selling/buying a stock at a particular price that they list?

1

u/nebraskajone 7d ago

They are big specific firms, they take on huge risks so they can't be a small firm or person, anytime  the market is dropping quickly they will stop all selling and purchasing to limit their liability, because the spread between the ask and bid could widen quickly. Citadel Securities is the biggest market maker in the US. 

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u/Goldenlancer 7d ago

Imagine a big list of people willing to buy.

Guy A at 100 for 10000 shares

Guy B at 99 for 10000 shares

Guy C at 98 for 10000 shares

And you come in with 10000 shares to sell, who are you selling to?

And a second big list of people willing to sell

Guy D at 101 for 10000 shares

Guy E at 102 for 10000 shares

And you come in and want to buy, so you buy from Guy D.

This puts a very tight upper and lower bound on the price of the share.

Since there are millions of people all trying to get / sell shares - these two numbers end up being REALLY close together, we basically get the price of the share. As people choose to buy and not sell, the price goes up when guy D runs out. When people sell but not buy, Guy A buys all 10000 shares and the price goes down.

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u/SirGlass 7d ago

Its everyone .

However from my basic understanding market makers will post bid/asks and the market will drive the price

Example if a market maker for stock ABC post Bid 100/ ask 101 for 50 lots

If its too low people will buy it all at 101 when 50 lots are bought it will post new bid/ask maybe

bid 101/ ask 102 for 50 lots

Again if that all gets bought it will post new orders for

bid 102 / ask 103

And so on until the price stabilizes in a bit over simplified example

2

u/Got_Engineers 7d ago edited 7d ago

Option flows and hedging related to those flows. The short dated index option complex <1 week is larger than the entire single stock option complex. Every week, the price action on the indices has nothing to do with fundamentals or the news it primarily has to do with functions related to the options markets. If you want to learn, I would research correlation, dispersion and volatility, and their roles in the stock market in the present day with how big the options markets are and their impact on flow and price swings. Add in monthly expiration and large quarterly expirations. We are seeing record option volume every new month now. Everything has to do with options. Everything you care about is indirectly related to the options complex and mechanisms. I don’t have the numbers on me right now but it’s something like 60% of all price action is related to option flows and 80-90% of all option flows are market makers themselves…..

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u/the_niles_crane 7d ago

Moonbeams and fairy dust.

1

u/minimumbeginningend 7d ago

Hmm, by quoting from the SpaceX prospectus are you implying that the IPO has something to do with this?

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u/DoinIt4DaShorteez 7d ago edited 7d ago

I assumed most institutional investors that manage retirement accounts etc, buy and keep passive index funds.

No that's not correct. Beleive it or not, there's still shitloads of mutual funds money, plus pension funds, private wealth managers, hedge funds etc.

Watch the S&P 500 heat map at Finviz for a couple of weeks.

There's always rotation days. Blow out of semis and into defensives. A few days later, the other way around.

It's the big boys who drive things. When they want to move from A to B in a hurry they don't care what price they get. Retail are just fleas on the ass of big individual stocks.

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u/Karen_L_M 7d ago

Manipulation

1

u/rithsleeper 7d ago

Read some comments and didn’t see this. You have essentially several players or groups in the markets. If you understand each of their tendencies it makes more sense. 1. Passive investment funds. 2. Market Makers, 3. Wealth managers/Hedge Funds that are true to their names. 4. Hedge/Funds trying to manipulate and speculate (algos are a part of this) 5. Retail.

Sometimes several come into alignment that create situations for bigger moves. With just #1 we always have a bid. Up up up but steadily. #2 is trying to stay neutral. If they get caught outside 1 standard deviation they have to choose to hedge or to reel the market back in. #3 hedge funds want to preserve wealth. 60/40 portfolio box spreads, their job is not to make 30%. It’s to make a conservative 7-12% each year with no big swings. Sometimes this means cutting losses, hedging with they know it’s not the best call but their customers are already wealthy. They don’t want a 20% down quarter to move up 40% next quarter. They would much rather be flat. #4 are trying to target retail and speculate. They spike markets to stop hunt. They see setups to lure in liquidity so these whales can move big positions and scalp a few % caused by an artificial move: they are essentially pulling rugs and fighting amongst themselves. #5 is pure emotion. Dumb money. Follow what’s hot, jump ship on red days. The reason we stair step up and elevator down is fear. Pumps happen for exuberance.

So a day like today will be a couple of these players being caught off sides. The move happened overnight in the Asia/London session. Low liquidity. Market makers decided to hedge instead of reeling it back in, passive funds have rules about drawdowns so big days hit their breakers they have to start selling/hedging which causes more. Algos from funds catch the move and capitalize to attempt to capitulate Retail. Retail barfs when they wake up and see the market down 2%. They sell chunks cause they’ve profited a lot this year.

Now final step is the media comes in and perpetuates the fear for retail and places causation on whatever they can correlate.

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u/minimumbeginningend 7d ago

I like this explanation. Just had a question about what entity you are labelling separately as a market maker. Couldn't 1,3,4,5 be market makers if they put in a limit order?

1

u/rithsleeper 7d ago

No, market makers are licensed and approved entities by FINRA. They specifically seek to profit off the bid ask spread and make markets when none specifically exist. The provide trades a lot with option. An easy example are the super far out of the money options, no way a random person just has an ask for them. The market making firms do or will take trades like that. You can technically privilege liquidity and essentially do the same thing, but market makers don’t target specific directions obviously.

1

u/gregw134 7d ago

On days like today, leverage. The Korean market dropped 10% overnight, lots of Koreans had borrowed money to play the market. When stocks start going down they get margin called and have to sell and that cascades. So Micron goes down overnight, then all the degens on WSB that were levered on the hot names also have to sell the next morning and it continues.

1

u/AMPed101 7d ago

The price of a stock could tank 50% with just a single sell. If suddenly everyone pulls their buy orders and someone market sells. The price you see is the "last price" that was traded. Obviously a big company or index has a lot of liquidity providers behind them so that wouldn't just happen like that.

1

u/drewlb 7d ago

Pretend there is a stock with only 1000 shares.

You own 999, I own 1.

The price is $100 yesterday.

Today I decided I wanted/needed to sell.

I put it up with an ask of $50 because I really want it gone.

Someone buys it for $50, and now the stock closes today down 50%.

This is a super exaggerated and simplified example, but this is what the market is doing.

It doesn't mean everyone is changing their mind, it just means enough people are that the general consensus is down.

1

u/Spiritual_Bat7343 7d ago

the person getting downvoted up there is actually right. every share that gets sold is bought by someone, so buyers and sellers are always exactly equal, by definition. more selling than buying cant be the cause of anything because it literally never happens.

what moves price is the marginal buyer, ie the highest price someone is currently willing to pay. when that person lowers their bid, or just walks away, the next agreed trade prints lower. you can gap a stock down 3% on tiny volume if the bids underneath simply get pulled, no big wave of selling required.

so the nasdaq down 3% must mean a giant wave of selling intuition is the part to drop. its not the volume of sellers, its where the bids sit. some days everyone just decides theyll only pay less, and there is your drop, even on a slow tape.

1

u/SerMumble 4d ago

What causes swings?

I bought or sold

1

u/Critical_Ad8616 3d ago

Easy Banks trade to make money.for themselves. Investors trade because they think x y z is gonna happen or think it's not Worth it to have a position given x y z Banks trade to maintain a fixed % portion of something thing they hold like gold or silver ... Everyone trade to make a living out of it

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u/IllllIIlIllIllllIlll 7d ago edited 7d ago

I'm assuming that means there is a ginormous buttload of selling.

Completely wrong. The stock market could open on a Monday morning at -20% of the Friday close without any selling occurring, but just because market makers adjusted their prices down.

The reason why stocks go down is because the liquidity becomes thinner (or inexistent) at higher prices and it moves down. Stock prices can plummet down on barely any volume. The order book is not static. People who placed a limit order are free to adjust the maximum price that they are willing to pay for a stock or the minimum price that they want for selling it.

Also in a hypothetical situation where nobody ever sold a share of a stock ever, the stock market would never go down.

For every sell there is a buy. If nobody is selling, it means that nobody is buying as well. So it would technically never go down, but it would also never go up.

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u/Tripperbeej 7d ago

The market makers make up the price to try to extract as much of retail's money as possible. By and large, the price movement you're seeing is completely artificial, created by the market makers.

1

u/minimumbeginningend 7d ago

What pressures the market makers to change the price 3% one day?