theory

My understanding of his argument (and I would love for somebody to correct me if you don't think I get the full picture!) is as follows, and is basically two-pronged:

First prong: The lower the minimum denomination of shares, the more total investors there can be (as most of society is impoverished and would like to, if possible, put some of their savings into banks and shares and such in order to grow their savings). The more total investors, the less united the control over a company can be, as many tiny shareholders will probably not show up to meetings. The less united the control, the more likely that a single corporation can take full control over it with relatively few shares. So, as you say, "More scattered investors holding small shares increases the power of the remaining finance capitalists that control ~40% shares?"

Second prong: The more people put their money into these shares, the more invested they are in the success of the corporation, so as to grow their savings. Therefore, the proletariat becomes kinda bourgeois-ified (most notable in Britain in Lenin's day, and in the US in the current day) because they know that imperialist international relationships - colonies and such - must be maintained. Therefore, naive "democratization" by making each worker a shareholder is actually counterproductive to socialism.

Chapter 5: Division of the World Among Capitalist Associations

Monopoly capitalist formations like cartels initially conquered their own national markets, and then expanded throughout the world. These national cartels formed deals between themselves, and further consolidated into international cartels - supermonopolies.

Lenin uses the example of the German electrical industries. Prior to 1900, there were several corporations backed by several banks in the electrical industry; then, there was a crisis in which smaller firms were ruined and the banks refused to support many of them with capital, resulting in only the banks’ closest allies thriving. By the 1910s, a monopoly had formed, with just two corporations (AEG and Siemens) existing and in very close cooperation. AEG grew to its massive position via the aforementioned holding system, comprising many subsidiary companies.

A similar process occurred in the United States, which created its own electric company, the GEC. In 1907, these two trusts formed an agreement which divided up the world between them, agreeing not to compete, and they exchanged inventions and information. Competition against this mega-trust is made enormously difficult.

These alliances are not permanent; trusts can still be brought to compete with each other if conditions change. Lenin uses the example of the oil industry, which is divided on an international scale between the Rockefellers and the Rothschilds, as well as several smaller companies such as in Baku, Austria, Romania, and those in Dutch colonies. Earlier, Deutsche Bank supported these smaller companies. These companies battle each other for larger monopolies by buying up oilfields. This eventually led to Deutsche Bank having to take the L (though they later tried to create a state oil monopoly which only led to various German corporations bickering about how to divide the profits, forestalling the plan until it was shelved due to the beginning of WW1). In the end, private and state monopolies are interwoven, supporting each other to create profit.

Lenin draws upon further examples of international trust formation, by talking about shipping companies, the international rail cartel, the steel cartel, and the zinc cartels. In most cases, the constituent companies agree to divide up the world and force any companies outside of the international cartel into submission, usually resulting in their collapse (and/or joining the international cartel).

Lenin points out that far from guaranteeing peace among nations - the argument essentially being that the development of international corporations means that they would not tolerate the disruptions in logistics and manpower that war would cause - the opposite is true. International competition and battle between cartels, and their division of the world, is the current form of the economic struggle that is inherent to a class system. Indeed, the international cartels divide up the world in accordance with both their own strength (e.g. their total capital invested, their manpower, etc) but also in accordance to the strength of their governments/militaries and the territory they control. Dividing international competition/cooperation into the categories of warlike/peacelike (and therefore saying that international monopolization is good between it might reduce war and increase peace) is nonsense, because as monopolization continues, national bourgeoisie are all still fundamentally in conflict for the highest profits, and this strategy of conflict fluctuates between the mere appearances of “peacelike” or “warlike”. Devastating military actions between governments aren’t some outside factor that the cartels are total victims to; they’re yet another way in which international cartels battle each other and seek to increase their strength. Meanwhile, non-military actions - the international cartels getting along nicely - still accelerate the impoverishment of the working classes. Either way, the poor are being disadvantaged - “peace” or “war”, it’s ALL class warfare.