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.