yanner39
Emperor
Having a security bureau has the same effect as having a sleeping spy in a city - they don't stack. There's no other passive defense, but the most efficient espionage defense is the counterespionage mission in enemy cities.
So the spy is still "protecting" the city from espionage if it's "sleeping"? Sorry if this is a stupid question but I always leave them in a city and every turn, click on "skip" turn for each spy. It gets pretty long when you have 8 or 9 spies.
multiplier buildings (eg, Banks and Wall Street) it's possible that the money you make in the HQ outweighs the ongoing cost in the branch city.
per turn, which is extremely versatile for converting to hammers (you can workshop over some farms, mine some windmills), commerce (cottage over some farms) or anything you desire by growing the population and assigning specialists. Basically, corporations can turn a mediocre tundra/desert city into something very worthwhile, or a normally great city into a real powerhouse.

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doesn't do much good, and in the late game working towns rivals running merchants well enough for me to not actively seek to build it in a food-rich merchant farm.