greater companies have it much much easier in the real world

 i lack the vocabular in that field to give proper examples but they pay less taxes, partly not even in their own country, get benefits for creating/not moving working places, the amount of fixcosts any company has matters less for bigger companies and much more

that doesnt mean there couldnt be a catchup mechanic, but that needs testing between equally skilled players

if one lacks the basics of the game, which many do at this point, they are supposed to lose

I just finished another round of games, and the last one I was losing badly. I started off the runaway player. I couldn't meet my power needs, and it was crippling. 

I was the last one left, I had 100K in debt, my stock price was a 1/3 of the leader and AI owned half of my company. I had one massive advantage that I capitalized on, I had massive amounts of water coming in, and I purchased the cold fusion and perpetual motion patent. So I ended up winning that game, because the AI couldn't meet the power demands at night, which ended up killing it's finances. And I furiously sold everything in my stock to buyout the remainder of Ms. Espionage's stock. It was an exhilarating win, especially after I had already accepted I was going to loose.

Let's not forget the random resources/claims that arrive spontaneously.

So I'm not sure it needs a catch up mechanic. Especially, since the game is meant to be played quickly. Also as pointed out prior, getting off to a poor start is simply part of the game. You can replace your buildings, but you can't catch up on resource production. In fact if such a mechanic were to be employed where the runaway player has his or her resource production reduced be it overhead or other means, or if the other player was augmented, then it would attack the very basis of the game and end up hurting the player you're trying to help. If you increase his buying power in anyway, he may depend on that change to his economy. Remember the change to his economy affects all of the economies. If you take it away at any point then you wind up crippling that player and his strategy.

Now let's say you reduce the production output of the lead player. Well if suddenly her surplus, becomes her lifeline. Now what she was selling to other people all willy-nilly, she may horde even more. Now the price on that commodity rises too. Then to and insult to injury she activates her hacker array, and drives the price up further. You end up hurting the other players.

Let's say we end up trying to do both to balance things out, well then you start to neutralize the free market. It becomes a little less volatile, which directly impacts the excitement of the gameplay.

About the only thing you can do, is give them one time with an additional claim, a black market item, or small amount of cash.

But to answer your question: Identify his strenght and use his size as a weakness. If he is not diversified look if power is costly and take out his power. If he is mass steel underground his iron, drive up iron price. instead of having a hughe surpluss he is now gaining that much more losses due to his size. If he is diversified go for one chain high in price and do not diversify. Since your one of many and not in lead and smaller than him he is probably not looking at your production. Thus you used your lesser size as an advantage.

Anyhow just suggestions. It IS hard to catch up.

The problem with catch up mechanics is that they make the game pointless, look at Risk boardgame for example, this is literally the most pointless game  in 3+ player format, as if played perfectly, the stall is never ending, only way you can win Risk is whine enough so that others think you are doing worse than you actually are.

Anyways, the current "catch up" mechanics are quite decent and what I like most about the game, is that the efficiency of all buildings a player has can change drastically from one point to the next, and so if you manage to have some very efficient tiles that are producing the right product, make successful hacker array transactions and some more then your tiles can easily be twice or three times more effective as the leading players. It is possible that in a 3 chem cluster, each of them are more efficient than offworld markets, it depends on the market really.

Then again, a player that has managed to get ahead more often than not is slightly better player, which means that he does the same things, +buys everything in the black market to make others pay more etc. + if he is really good player he will be having a lead without an average player or even some very good players even noticing it. The good part about this game is, that when it does happen, it is over shortly.

I also see this as a problem it seems if you aren't a top company 5-10 minutes into the game you're doomed.  The down side is I don't know of a fix all solution to this.  Here are a few suggestions.

• Make the higher end products available later in game, offering 1 or 2 players the right to bid on early rights to create these resources.
• Create a black market option to inflate stock or block buy out options for x amount of time. (as long as you own half of your company).
• This would cost more, the more you use it similar to other black market options.  (so just a temporary hold off)
• Have it expire longer than it takes you to renew if you have the funds.  (Allows one to continue down this path as long as they can afford to.)
• Gives more encouragement to purchase your own stock earlier on to help block this.
• Create random events to attempt to aid smaller companies.  (not to give them the lead but, may help keep them in the game or feeling it's over.)

Other suggestions...

• Have a warning message when a company is able to buy you out or getting close.
• Create more demand for resources later in the game to offset the inflated supply.