Corporation have a different use at different era starts

[SPQR300]

Corporations are heavily effected by inflation. If you have a typical of let's say 3 needed resources, you pay like -7,8,9gold maintenance with courthouses.
-If the game was a modern era start, then there is hardly any inflation, you get the corporation benefit and -8,9,10gold in the cities, and +15gold in the HQ. So you spread it everywhere you can, home and abroad. Your balance is always positive.
-If the game was an ancient era start, by the time corporations come, the inflation is much higher. Later it can be like ~100-150%. So instead of the -7,8,9gold corporational maintanance cost, you have to pay like 15-20gold/turn, even with courthouses. The +15gold/turn in the HQ doesn't make up for this. So you only spread your corporations to cities which really need the corp. benefit, but you rather spread it abroad, where it can wreak an economic havoc.

With corporations, inflation so heavily effects gameplay and strategies, that I became really curious on how it exactly works.

 

[Random Oracle]

This is a very good observation and gives further evidence to the theory that corporation maintenance combined with inflation is currently broken. I'd also add that different Ancient era games can reach Corporations in very different times depending on the difficulty level (AI techs faster at higher levels), game conditions (world wars tend to mean slower tech rate compared to peaceful, tech trading partners) and player skill. I imagine corporations would play a very different role when founded at 1500 AD than at 1900 AD.

 

[werdna]

and the cost also varies by map size. If you play on huge map, you most likely have more resources. I once played on huge big&small map and had a lot of see resources. Each instance of sushi corp. in my city cost me about 150 gold in later stages of game. it was insane. I had spread it to quite a few cities in earlier ages and later on it killed my research.
Plus, before you spread that corp. to a city the tooltip would say the cost is around 40, but after I add it to city my gold dropped by 150.