| Abbreviation | Definition |
|---|---|
| IROQ | Iroquois Bancorp, Inc. |
| IRSN | Irvine Sensors Corporation |
| IRTN | In Sports International, Inc. |
| IRWN | Irwin Financial Corporation |
| IRWNP | Irwin Financial Corporation Preferred |
| ISAC | I C Isaacs & Company, Inc. |
| ISAI | I S A International, Inc. |
| ISBC | Investors Bancorp, Inc. |
| ISBF | I S B Financial Corporation |
| ISBH | ISBRE Holding Corporation |
| ISBL | Ise Blu Equity Corporation |
| ISBO | ISB Financial Corporation of Iowa |
| ISCA | International Speedway Corporation Class A |
| ISCB | International Speedway Corporation Class B |
| ISCO | Illinois Superconductor |
| ISCRY | I S C O R, Ltd. |
| ISEE | Sterling Vision, Inc. |
| ISEE | Sterling Vision, Incorporated |
| ISFB | Internet Solutions for Business |
| ISFC | Innes Street Financial Company |