Whilst playing the game, I've noticed that there is very little immediate consequence for early game weakness when compared to other RTS games, I feel this leads to a general base upgrade focus (which in turn leads to the resources that are used in base upgrades becoming more valuable). 

So to counter this, an early game threat is needed, and it needs to be existential, so the black market doesn't count. The current company stock system tends to play out mostly in one direction; essentially every stock bought in your company brings you a little closer to destruction (though obviously you can buy back all at once).

I propose a stock system which would encourage more of a back and forth struggle for control of a company before it gets bought out, the hope being that a player is throughout the game always concerned that any reduction in stock price could be exploited by a foe.

Initial details

The most immediately noticeable difference about this new system would be that all the players start with complete ownership of their own stock.

Attacking

When a player wants to attack another they can click on the stock buying button, which would start a size 1 attack, which if successful would lead to the attacker getting 1 of the defenders stock. Each additional click of the stock buying button during the attack would increase the size of the attack by 1, meaning more stock would be won upon success (but costing more). The defender would be able to use the same mechanic to counter attack, and either stop the attack in its tracks or win it back afterwards.

The stock attacks of other companies than the one the bar represents, would always come from the left whereas counter attacks from the company would always come from the right, this would mean that multiple attacker would often be wiping out each others investments on the left, whilst the company would be able to stand back and let them lose the money.

Defending

The counter-attacking described in the 'Attacking' section should really be more of an act of desperation; players should have the ability to prepare for a stock attack before it happens. The way to do this would be Fortifying stock. The player would invest money to protect their shares in a particular stock bar (so, investing in player 1's bar wouldn't effect stock in player 2's) thereby making the stock they hold there harder (more expensive) to attack. Because the fortification investment is done per bar, a player would have to weigh protecting their investments in another company against protecting stock in their own company.

Summary

Each of the sections above has a purpose in shifting gameplay:

Initial details - skips the initial buying up so that you don't have a pre-attacking phase

Attacking - creates more granularity in stock buying/selling.

Defending - rewards the players for putting money aside for stock defense.

I believe if these systems where implemented, stock buying could become less of a finishing move and more of a constant struggle for control of the various players companies throughout the match.