The Central Bank, unlocked after you research Economics. Buildable in either City Square, Commercial hub or Government plaza. Allows the ability to to borrow or take a loan out against your Empire. Each loan requires gold per turn. Base the gold amount and requirement of gold per turn on how many commercial buildings you have in the capital or all of your cities in general. EXAMPLE: 1 Market in capital allows to borrow 500 gold at a rate of 15 GPT over the course of 50 turns. You end up paying 750 gold in the end, but perhaps you needed the upfront cash for a war that you wouldn't of otherwise won. As more commercial hub buildings get built, the lower GPT requirements and higher the amount borrowed. If someone really wanted to get in depth you could add other parameters that make it more risky. Example: If too much housing is available the rate of GPT requirement would go up. Reflecting oversupply in housing market and a housing crash. And/or your citizens are unhappy by a certain degree and the GPT requirement would go up as well. I think if adding greater risks, then would have to increase the reward as well. I think this mod would represent a more modern and Western style of government where cash flow is more readily accessible short term. Again there should be risks involved and not suitable for all investors- in that case you should stick with the gold standard.