Sigma Development Investor List
| Pledge | Fist | Last |
| 1952 | Dean | Lindsay |
| 1954 | Bill | Umbarger |
| 1956 | Ron | Burfeind |
| 1957 | Larry | Moore |
| 1958 | Bobbie | Scheiderer |
| 1959 | David | Huecker |
| 1960 | Rex | Ricketts |
| 1961 | Kenneth | Bray |
| 1961 | Charles | Huecker |
| 1962 | Carl | Gehardt |
| 1962 | Jim | Powell |
| 1962 | Fred | Minear |
| 1962 | Warren | Wolf |
| 1963 | Kenny | Lentz |
| 1964 | George | Brown |
| 1965 | Colin | Collins |
| 1965 | Ed | Robinson |
| 1965 | Ron | Franklin |
| 1965 | Kim | Ricketts |
| 1965 | Mike | Davis |
| 1965 | Bob | Zeysing |
| 1966 | Eddie | Brickner |
| 1966 | Steve | Cronin |
| 1966 | Jerry | Espe |
| 1966 | James | Hodges |
| 1966 | Chuck | Kessinger |
| 1966 | Paul | Langewisch |
| 1966 | Fred | Utlaut |
| 1967 | Phil | Noellsch |
| 1968 | Terry | Heiman |
| 1968 | Ralph | Eagen |
| 1968 | Steve | Jones |
| 1968 | Chuck | Owings |
| 1968 | Eddie | Yoder |
| 1969 | Gary | Myers |
| 1970 | Ted | Abele |
| 1970 | James | Brackenridge |
| 1970 | Ron | Ketchum |
| 1970 | Bob | Cooper |
| 1970 | Wiley | McVicker |
| 1970 | Chris | Mueller |
| 1970 | Gerald | Myers |
| 1971 | Mike | Boulware |
| 1971 | Neil | Bredehoeft |
| 1971 | David | Coffelt |
| 1971 | Steve | Hood |
| 1971 | David | Riekoff |
| 1971 | Don | Nikodim |
| 1971 | Dennis | Stewart |
| 1971 | Alan | Wessler |
| 1972 | Robert | Barrett |
| 1972 | Jerry | Duff |
| 1972 | Tom | Ogle |
| 1973 | Gene | Bredehoeft |
| 1973 | Mark | Cadle |
| 1975 | Robert | Doane |
| 1975 | Doug | Gutshall |
| 1975 | Lynn | Rogers |
| 1975 | Kent | Templeton |
| 1976 | Hurst | Family |
| 1976 | Larry | Schuster |
| 1976 | Wyatt | Phillips |
| 1977 | Bruce | Berg |
| 1977 | Mark | Wittmeyer |
| 1979 | Jim | Wheeler |
| 1980 | Brett | Begemann |
| 1980 | Greg | White |
| 1980 | Roger | Gardner |
| 1980 | Randy | Zimmer |
| 1983 | Terry | Ecker |
| 1984 | Bill | Diechman |
| 1985 | Todd | Graves |
| 1986 | Dennis | Henks |
| 1986 | Minear | Brent |
| 1989 | Stuart | Schooley |
| 1989 | Kale | Walch |
| 1992 | Michael | Rolf |
| 1993 | Dan | Graves |
| 1998 | Cheston | Easter |
| 1998 | Steve | Neimeyer |
| 1998 | Trent | Brackenridge |
| 1998 | Keith | Templin |
| 1998 | Travis | Rowland |
| 1998 | Lucas | Schmidt |
| 1998 | Andy | Heins |
| 2001 | Mark | Claypole |
| 2001 | Jim | Noellsch |
| 2002 | Adam | Ahrens |
| 2002 | Jonathan | Dierking |
| 2003 | Bill | Govern |
| 2003 | Andrew | Kacena |
| 2003 | Matthew | Kays |
| 2006 | Brady | Bounds |