Direct benefit: liquidity - whether you need to buy or to sell, you have a place where you'll find a counterpart quickly.
Indirect benefit: information - just watching the bets lets you have an idea about how much people with skin in the game value things, letting you take better decisions about resources allocation.
The knowledge that I can get out of my investment any time I want at the current market price makes me much more willing to invest in the first place. If I know that it can take several month to get out of an investment or that I have to sell at a discount to get a fast deal then I'm more likely to sit on more of my money in case I need it quickly.
However, the reality is if the market disappeared today informal markets would quickly take it's place consider what happens to pre IPO stock.
Additionally, IPOs are almost priced incorrrectly, and show the problems with the informal market.
I can't imagine selling a position would have any influence on price until it's a significant percentage of the market cap. The median cap of the Russell 2000 (an american small cap index) is 809 M [0].
Do most people really have multi-million positions in a single small cap company?
Anyway, my point is simply that trades are the mechanism that changes price. So, you can't expect to sell arbitrary amounts of stock at the current clearing price.
+/- a few cents might not seem like much but drops can spiral with relatively small initial sales.
The reality is the current ticker price is only meaningful up to mid sized transactions.
Illiquid investments need to generate higher returns to make up for the fact they're illiquid, in comparison to liquid ones.
How would any of the other trading help my business, or anyone else?
Ceteris paribus, volatility is negatively correlated to trading volumes: if your shares are only exchanged twice a week (actual trading volumes for a small company on some exotic exchange) the price variations will inevitably happen in large steps, which does not reassure investors. And if the company is not publicly traded, who knows what the price of the next transaction will be ?
A lively market for an investment vehicle opens the possibility of derivatives, which are valuable to investors interested in the company but whose appetite for risk is limited. So if your company's shares trade has derivatives, it makes them more attractive.
The presence of the secondary market makes the initial offering (sales) of shares easier.
Imagine company A is making a primary offering (direct sales of shares from the company to an investor), but that those shares do not have a ready secondary market.
Imagine company B is making the same primary offering, but there is a deeply liquid secondary market.
Company A and Company B are otherwise identical (line of business, revenue, profit, outlook for the future, etc). Investors will much more readily invest in company B.
(Similar to how money or even bitcoin is only useful if you can pass it on.)
Indirect: that seems like a losing game. Why would gambling on a companies future ever help anyone(except the lucky?).
Most transactions in the market are not gambling. Trades happen, yes, but that is because the prospects of companies are continually changing. When it became apparent pretty much everyone would move to Netflix and streaming video, would you want to continue holding Blockbuster stock? No; you would want to sell it.
People who simply "gamble" in the market lose money about as often as they gain it, and soon stop. Hedge funds and mutual funds generally try to invest in shares on a longer-term basis rather than continually trading them; trading incurs transaction costs, and if an investment was correct and is generating better-than-benchmark returns there is no reason to sell it.
The "day trading" books you might see at your local Barnes and Noble are get-rich-quick books and are not representative of the actual professional investment industry.
For every seller, there's a buyer. The market will settle on a price at which those are evenly matched---even if that's close to zero.
You have to offer a good enough price on your Blockbuster stock to find a buyer who thinks it's a good idea. (Unless it's someone who has to cover a short position, those guys are basically forced to buy. But they'll still buy from the seller with the best price.)
Prediction markets are the most efficient way to make societal decisions; they allow everyone to combine their information and predictions without having to directly coordinate with each other. There's academic literature arguing they'd be the best way to do politics etc. At the moment all we do with them is capital allocation, but that has real-world effects: ultimately the idea is to give more money to companies that can use it better (so that they then e.g. build more factories, hire more people, make relevant buyouts) and less money to companies that will make less good use of it.
Similarly, a company that does well socially (e.g, a public hospital) but not economically would get obliterated in the stock market.
That would be regulatory failure - it is not the market's fault if the government is weak... Fix the government, get decent labor laws, let companies internalize externalities, regulate environmental impact !
> Similarly, a company that does well socially (e.g, a public hospital) but not economically would get obliterated in the stock market
Which is why, in civilized countries, public services are provided by the government or on behalf of the government.
Foisting government responsibilities upon the market is bound to create disappointment...
In any moment it seems like you're just buying thin air for money and selling that air later for (hopefully) more money. But that's the short-term view of it. In the long run you are taking a stake in a company that you hope as a whole will be worth more in the future than it is today. That stake gives you legal right of ownership to a percentage of that company and its cashflows. If it's a dividend paying company you collect regular profits from it as well.