The fund is Thompson Street’s fifth and largest to date. : Partly cloudy with late night showers or thunderstorms. Low 63F. Winds SSE at 10 to 15 mph. Chance of rain 50%.. Partly cloudy with late night showers or thunderstorms. Low 63F. Winds SSE at 10 to 15 mph. Chance of rain 50%. Thompson Street Capital Partners, a private equity firm based in Clayton, has started raising money toward a new $1.1 billion fund that would make it one of the largest investment tools in the St. Louis area. The fund is Thompson Street’s fifth and largest to date.