Sigma V was a planet in sector 861, outside of but proximate to Federation space. It was notable for having very little crime, and very minor offenses when there was illegal activity.
In 2376, Ardack Sprachnee, the Sigma V minister of finance, plotted to steal the entire planetary treasury, a sum of five billion bars of gold-pressed latinum. To do so, he sent out a tribblecom program embedded in a text letter, claiming the planet's democratic republic government had come under siege by a military power.
While trying to resolve a hostage situation on Recreational Station Hidalgo, the Federation government persuaded Sigma V to release a group of prisoners, including Sprachnee, and have them transported to Bartha IX. Once that situation was resolved, Sprachnee was arrested and the latinum he had attempted to steal returned to the treasury. (SCE eBook: Identity Crisis)
- It is unclear whether there was any actual political upheaval on Sigma V as claimed in Sprachnee's letter or not.