I'll run this experiment on Dwilight in Nifelhold.
Taxes were just collected today. I run a rate of 14%, have no problems with control (since it's the capital). I don't think that many investments, if any, have been done here recently. I would expect this to net me a tidy profit.
Region Tax Report (8 hours, 12 minutes ago)
message to the lord and knights of Nifelhold
The following taxes were collected in Nifelhold. The tax rate for this collection was 14 % and the lords share was 10 %.
Regional income and expenses
Peasants Taxes 246 gold
Taxes from Guildhouses + 1 gold
Buildings Upkeep - 10 gold
Militia Payment - 46 gold
Collectable Tax Gold 191 gold
Estate of Size Peasants Tax Collected Knight Share Lord Share
Walter 40 % 2520 76 gold 68 gold 8 gold
Rohk 36 % 2268 68 gold 68 gold
Wild Lands 24 % 1512 22 gold 22 gold
Region Totals 166 gold 68 gold 98 gold
You have now invested 210 gold in this region, boosting production by 118 % to 218 %. Your advisors hope for a return of ca. 190 gold, if everything works well.
To ensure that your investment pays off, you should try to keep morale and realm control high and prevent enemies from looting. With its boosted production, Nifelhold is sure to be a prime target.
Bring it on, Summerdale