| 8WS | | International Consolidated Airlines SA Mini | Mini Single Stocks | IFLO | |
| SMN | | International Paper Company | Single Stock Options | IFLO | |
| ITR | | Intertek Group | Single Stock Options | IFLO | |
| IVS | | Investec PLC - STND OPT | Single Stock Options | IFLO | |
| IRB | | Iroquois (Into) Basis (Platts) Future | Natural Gas | IFED | |
| IRI | | Iroquois (Into) Index (Platts) Future | Natural Gas | IFED | |
| XV6 | | Iroquois (Into) Physical Basis LD1 | Natural Gas | IEPA | |
| XV5 | | Iroquois (Into) Physical Fixed Price Monthly | Natural Gas | IEPA | |
| XV4 | | Iroquois (Into) Physical Fixed Price Spot | Natural Gas | IEPA | |
| XV8 | | Iroquois (Into) Physical Gas Daily Monthly | Natural Gas | IEPA | |
| XV7 | | Iroquois (Into) Physical Gas Daily Spot | Natural Gas | IEPA | |
| IRS | | Iroquois (Into) Swing (Platts) Future | Natural Gas | IFED | |
| IZB | | Iroquois-Z2 Basis (Platts) Future | Natural Gas | IFED | |
| IZI | | Iroquois-Z2 Index (Platts) Future | Natural Gas | IFED | |
| IZS | | Iroquois-Z2 Swing (Platts) Future | Natural Gas | IFED | |
| ISD | | Iso Butane, OPIS Conway In-Well Balmo Future | Natural Gas Liquids | IFED | |
| ISP | | Iso Butane, OPIS Mt. Belvieu Non-TET Balmo Future | Natural Gas Liquids | IFED | |
| ISQ | | Iso Butane, OPIS Mt. Belvieu TET, Fixed Price Future (Balmo) | Natural Gas Liquids | IFED | |
| ICO | | ISO New England Connecticut Day-Ahead Off-Peak Fixed Price Future | Electricity | IFED | |
| ICP | | ISO New England Connecticut Day-Ahead Peak Fixed Price Future | Electricity | IFED | |
| IED | | ISO New England Maine Day-Ahead Off-Peak Fixed Price Future | Electricity | IFED | |
| IEB | | ISO New England Maine Day-Ahead Peak Fixed Price Future | Electricity | IFED | |
| POP | | ISO New England Massachusetts Hub Day-Ahead Off-Peak Daily Fixed Price Future | Electricity | IFED | |
| NOP | | ISO New England Massachusetts Hub Day-Ahead Off-Peak Fixed Price Future | Electricity | IFED | |
| NO2 | | ISO New England Massachusetts Hub Day-Ahead Peak 2x16 Fixed Price Future | Electricity | IFED | |
| EDP | | ISO New England Massachusetts Hub Day-Ahead Peak Daily Fixed Price Future | Electricity | IFED | |
| NEZ | | ISO New England Massachusetts Hub Day-Ahead Peak Daily Mini Fixed Price Future | Electricity | IFED | |
| NEP | | ISO New England Massachusetts Hub Day-Ahead Peak Fixed Price Future | Electricity | IFED | |
| NOH | | ISO New England Massachusetts Hub Real-Time Off-Peak Daily Fixed Price Future | Electricity | IFED | |
| NOG | | ISO New England Massachusetts Hub Real-Time Off-Peak Fixed Price Future | Electricity | IFED | |
| NMD | | ISO New England Massachusetts Hub Real-Time Peak Daily Fixed Price Future | Electricity | IFED | |
| NOF | | ISO New England Massachusetts Hub Real-Time Peak Fixed Price Future | Electricity | IFED | |
| IND | | ISO New England NE Massachusetts Day-Ahead Off-Peak Fixed Price Future | Electricity | IFED | |
| INB | | ISO New England NE Massachusetts Day-Ahead Peak Fixed Price Future | Electricity | IFED | |
| IHD | | ISO New England New Hampshire Day-Ahead Off-Peak Fixed Price Future | Electricity | IFED | |
| IHB | | ISO New England New Hampshire Day-Ahead Peak Fixed Price Future | Electricity | IFED | |
| RIZ | | ISO New England Rhode Island Day-Ahead Off-Peak Fixed Price Future | Electricity | IFED | |
| RIY | | ISO New England Rhode Island Day-Ahead Peak Fixed Price Future | Electricity | IFED | |
| IMD | | ISO New England SE Massachusetts Day-Ahead Off-Peak Fixed Price Future | Electricity | IFED | |
| IMB | | ISO New England SE Massachusetts Day-Ahead Peak Fixed Price Future | Electricity | IFED | |
| IWD | | ISO New England West Central Massachusetts Day-Ahead Off-Peak Fixed Price Future | Electricity | IFED | |
| IWB | | ISO New England West Central Massachusetts Day-Ahead Peak Fixed Price Future | Electricity | IFED | |
| ISC | | Isobutane, OPIS Conway In-Well Future | Natural Gas Liquids | IFED | |
| ISO | | Isobutane, OPIS Mt. Belvieu Non-TET Future | Natural Gas Liquids | IFED | |
| ISL | | Isobutane, OPIS Mt. Belvieu TET Future | Natural Gas Liquids | IFED | |
| IPR | | Italian Power Financial Base 1x Cal Options | Electricity | NDEX | |
| IPQ | | Italian Power Financial Base 1x Qtr Options | Electricity | NDEX | |
| DIF | | Italian Power Financial Base Daily Futures | Electricity | NDEX | |
| IPB | | Italian Power Financial Base Futures | Electricity | NDEX | |
| IPB | | Italian Power Financial Base Options | Electricity | NDEX | |