Insider trading in another company?
"This information is clearly ""material"" (large impact) and ""non-public"" according to the statement of the problem.  Also, decisions like United States v. Carpenter make it clear that you do not need to be a member of the company to do illegal insider trading on its stock. Importantly though, stackexchange is not a place for legal advice and this answer should not be construed as such.  Legal/compliance at Company A would be a good place to start asking questions."
When a company IPOs the underwriters sell a given percentage on IPO day and shortly thereafter. Whatever is sold on IPO day trades freely.   Insiders, employees and investors who bought before the IPO only sell a percentage of their shares on IPO day. They all also agree to 'lock up' the remainder for a period of time, so that not everyone is rushing to the exits right away. Well, if you're an employee you don't per-se agree, it's just how your stock options are setup and you don't really have a say in the matter. Shares in a company represent a portion of a company. If that company takes in money and doesn't pay it out as a dividend (e.g. Apple), the company is still more valuable because it has cold hard cash as an asset. Theoretically, it's all the same whether your share of the money is inside the company or outside the company; the only immediate difference is tax treatment.  Of course, for large bank accounts that means that an investment in the company is a mix of investment in the bank account and investment in the business-value of the company, which may stymie investors who aren't particularly interested in buying larve amounts of bank accounts (known for low returns) and would prefer to receive their share of the cash to invest elsewhere (or in the business portion of the company.) Companies like Apple have in fact taken criticism for this. Your company could also use that cash to invest in itself (growing the value of its profits) or buy other companies that are worth money, essentially doing the job for you. Of course, they can do the job well or they can do it poorly... A company could also be acquired by a larger company, or taken private, in exchange for cash or the stock of another company. This is another way that the company's value could be returned to its shareholders. I think you're looking for the public float: Public float or the unqualified term may also refer to the number of   outstanding shares in the hands of public investors as opposed to   company officers, directors, or controlling-interest investors.   Assuming the insider held shares are not traded, these shares are the   publicly traded ones. The float is calculated by subtracting   restricted shares from outstanding shares. As mentioned, Treasury stock is probably the most narrow definition of restricted stock (not publicly traded), but shares held by corporate officers or majority investors are often included in the definition as well. In any case, the balance sheet is indeed a good place to start. News about a company is not the only thing that affects its stock's price. There is also supply and demand.  That, of course, is influenced by news, but it is not the only actor.  An insider, with a large position in their company's stock, may want to diversify his overall portfolio and thus need to sell a large amount of stock.  That may be significant enough to increase supply and likely reduce the stock's price somewhat. That brings me to another influence on stock price: perception.  Executives, and other insiders with large positions in their company's stock, have to be careful about how and when they sell some of that stock as to not worry the markets.  Many investors watch insider selling to gauge the health of the company. Which brings me to another important point.  There are many things that may be considered news which is material to a certain company and its stock.  It is not just quarterly filings, earnings reports and such.  There is also news related to competitors, news about the economy or a certain sector, news about some weather event that affects a major supplier, news about a major earthquake that will impact the economy of a nation which can then have knock-on effects to other economies, etc... There are also a lot of investors with varying needs which will influence supply and demand.  An institutional investor, needing to diversify, may reduce their position in a stock and thus increase supply enough that it impacts the stock's price.  Meanwhile, individual investors will make their transactions at varying times during the day.  In the aggregate, that may have significant impacts on supply and demand. The overall point being that there are a lot of inputs and a lot of actors in a complicated system.  Even if you focus just on news, there are many things that fall into that category. News does not come out at regular intervals and it does not necessarily spread evenly.  That alone could make for a highly variable environment. "As far as I know, the answer to this is generally ""no.""  The closest thing would be to identify the stock transfer company representing the company that you want to hold and buy through them. (I have held this way, but I don't know if it's available on all stocks.)  This eliminates the broker, but there's still a ""middle man"" in the transfer company. Note this section from the Stock transfer agent Wikipedia article: A public company usually only designates one company to transfer its stock. Stock transfer agents also run annual meetings as inspector of elections, proxy voting, and special meetings of shareholders. They are considered the official keeper of the corporate shareholder records. The decision to have a single transfer company is a practical one, ensuring that there is one entity responsible for recording this data - Hence even if you could buy stock ""directly"" from the company that you want to own, it would likely still get routed through the transfer company for recording." Assuming this is a public company, i'd recommend reading the analyst calls from the last several quarters. This will give you an idea of what investors, and therefor likely the board and senior leadership, are focused on at a very high level. Youre an intern, so dont feel like you need to blow the doors off, but showing that you are aware of the company's major objectives and asking some thoughtful questions about them is probably a good start. Initially, Each company has 10k shares. Company B has $500k money and possibly other assets. Every company has stated purpose. It can't randomly buy shares in some other firm.   Company A issued 5k new shares, which gives it $500k money. Listed companies can't make private placements without regulatory approvals. They have to put this in open market via Public issue or rights issue. Company B does the same thing, issuing 5k shares for $500k money. Company A bought those 5k shares using the $500k it just got There is no logical reason for shareholder of Company B to raise 5K from Company A for the said consideration. This would have to increase. Your first scenario, involving shareholders in a private corp being limited by a contractual agreement, is common in practice. Frequent clauses include methods of valuing the shares if someone wants to sell, first right of refusal [you have to attempt to sell to the other shareholders, before you can sell to a 3rd party], and many others. These clauses are governed by contract law [ie: some clauses may be illegal in contract law, and therefore couldn't be applied here]. A Universal Shareholders' Agreement is just the same as the above, but applied to more people. You would never get an already public company to convert to a universal shareholders' agreement - because even 1 share voting 'no' would block it [due to corporate law limiting the power of a corporation from abusing minority shareholder value]. In practice, these agreements universally exist at the start of incorporation, or at least at the first moment shares become available. An example is the Canadian mega-construction company PCL*, which is employee-owned. When the original owner transferred the corporation to his employees, there was a USA in place which still today governs how the corporation operates.  In theory you could have a 'public company' where most shares are already owned by the founders, and 100% of remaining shares are owned by a specific group of individuals, in which case you may be able to get a USA signed. But it wouldn't really happen in practice.  *[Note that while PCL is broadly owned by a large group of employees, it is not a 'public company' because any random schmuck can't simply buy a share on the Toronto Stock Exchange. I assume most exchanges would prevent corporations from being listed if they had ownership restrictions like this].