----

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| [X] | Annual Report Pursuant to Section 15(d) of the Securities Exchange Act of 1934 |
|-----|--------------------------------------------------------------------------------|

| [   ] | Transition Report Pursuant to Section 15(d) of the Securities Exchange Act of 1934 |
|----------------------|------------------------------------------------------------------------------------|

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Table of Contents

| Financial Information                   |                                                                                |
|-----------------------------------------|-------------------------------------------------------------------------------------|
|                                    |                                                                                |   |   |
| Nicor Companies Savings Investment Plan |                                                                                |
|                                    | Cover Page                                                                          | 1 |
|                                    | Report of Independent Registered Public Accounting Firm                             | 2 |
|                                    | Financial Statements                                                                | 3 |
|                                    | Notes to Financial Statements                                                       | 4 |
|                                    | Form 5500, Schedule H, Part IV, Line 4(i), Schedule of Assets (Held at End of Year) | 11 |
|                                    |                                                                                |   |   |
| Nicor Gas Thrift Plan                   |                                                                                |
|                                    | Cover Page                                                                          | 12 |
|                                    | Report of Independent Registered Public Accounting Firm                             | 13 |
|                                    | Financial Statements                                                                | 14 |
|                                    | Notes to Financial Statements                                                       | 15 |
|                                    | Form 5500, Schedule H, Part IV, Line 4(i), Schedule of Assets (Held at End of Year) | 22 |
|                                    |                                                                                |   |   |
| Other Information                       |                                                                                |
|                                    | Signature                                                                           | 23 |
|                                    | Exhibit Index                                                                       | 24 |
|                                    |                                                                                |   |   |

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Nicor Companies

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Table of Contents

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

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Table of Contents

| Nicor Companies Savings Investment Plan                                    |   |
|----------------------------------------------------------------------------|--------|
| Statements of Net Assets Available for Benefits                            |   |
|                                                                       |   |   |   |   |   |   |
|                                                                       |   |   |   |   |   |   |
|                                                                       |   | December 31 |   |
|                                                                       |   | 2010 |   |   | 2009 |   |
| Assets:                                                                    |   |   |   |   |   |   |
| Participant-directed investments in Master Trust, at fair value            |   | $ | 191,131,284 |   |   | $ | 169,632,778 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Receivables:                                                               |   |   |   |   |   |   |   |   |
| Notes receivable from participants                                         |   |   | 3,240,614 |   |   |   | 2,870,907 |   |
| Employer contributions                                                     |   |   | 646,949 |   |   |   | 575,123 |   |
| Participant contributions                                                  |   |   | 228,041 |   |   |   | 226,442 |   |
|                                                                       |   |   | 4,115,604 |   |   |   | 3,672,472 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Net assets available for benefits, at fair value                           |   |   | 195,246,888 |   |   |   | 173,305,250 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Adjustment from fair value to contract value for the stable value fund     |   |   | (2,294,915 | ) |   |   | (1,196,626 | ) |
|                                                                       |   |   |   |   |   |   |   |   |
| Net assets available for benefits                                          |   | $ | 192,951,973 |   |   | $ | 172,108,624 |   |
|                                                                       |   |   |   |   |   |   |   |   |
|                                                                       |   |   |   |   |   |   |   |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Statements of Changes in Net Assets Available for Benefits                 |   |
|                                                                       |   |   |   |   |   |   |   |   |
|                                                                       |   |   |   |   |   |   |   |   |
|                                                                       |   | Year ended December 31 |   |
|                                                                       |   |   | 2010 |   |   |   | 2009 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Net increase in Plan assets from investment activities of the Master Trust |   | $ | 19,480,775 |   |   | $ | 25,037,915 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Contributions:                                                             |   |   |   |   |   |   |   |   |
| Participant                                                                |   |   | 7,742,040 |   |   |   | 7,174,357 |   |
| Employer                                                                   |   |   | 4,278,512 |   |   |   | 4,028,503 |   |
|                                                                       |   |   | 12,020,552 |   |   |   | 11,202,860 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Interest income on notes receivable from participants                      |   |   | 157,350 |   |   |   | 156,696 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Benefits paid to participants                                              |   |   | (10,988,278 | ) |   |   | (7,747,052 | ) |
|                                                                       |   |   |   |   |   |   |   |   |
| Transfers in                                                               |   |   | 172,950 |   |   |   | 328,173 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Net increase                                                               |   |   | 20,843,349 |   |   |   | 28,978,592 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Net assets available for benefits at beginning of year                     |   |   | 172,108,624 |   |   |   | 143,130,032 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Net assets available for benefits at end of year                           |   | $ | 192,951,973 |   |   | $ | 172,108,624 |   |
|                                                                       |   |   |   |   |   |   |   |   |
|                                                                       |   |   |   |   |   |   |   |   |
| The accompanying notes are an integral part of these statements.           |   |   |   |   |   |   |   |   |

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Table of Contents

1.  DESCRIPTION OF THE PLAN

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Table of Contents

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Table of Contents

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Table of Contents

|                                                                                        |   | 2010   |        |   | 2009   |   |
|---------------------------------------------------------------------------------------------|--------|--------|-------------|--------|--------|--------|
| Assets:                                                                                     |   |   |        |   |   |   |
|   General investments (at fair value):                                            |   |   |        |   |   |   |
|     Stable value fund*                                                  |   | $      | 114,953,405 |   |   | $      | 110,463,871 |   |
|     Nicor Inc. common stock*                                            |   |   | 25,517,357  |   |   |   | 23,437,407 |   |
|     Registered investment companies*                                    |   |   | 196,399,172 |   |   |   | 168,474,108 |   |
|                                                                                        |   |   |        |   |   |   |   |   |
| Net assets in the Master Trust, at fair value                                               |   |   | 336,869,934 |   |   |   | 302,375,386 |   |
|                                                                                        |   |   |        |   |   |   |   |   |
| Adjustment from fair value to contract value for the stable value fund                      |   |   | (4,526,648  | )      |   |   | (2,388,026 | ) |
|                                                                                        |   |   |        |   |   |   |   |   |
| Net assets in the Master Trust                                                              |   | $      | 332,343,286 |   |   | $      | 299,987,360 |   |
|                                                                                        |   |   |        |   |   |   |   |   |
| Plan’s interest in the Master Trust’s net assets, at fair value            |   | $      | 191,131,284 |   |   | $      | 169,632,778 |   |
|                                                                                        |   |   |        |   |   |   |   |   |
| Plan’s percentage interest in the Master Trust’s net assets, at fair value |   |   | 57          | %      |   |   | 56 | % |
|                                                                                        |   |   |        |   |   |   |   |   |
|  *  Party-in-interest investments.                                           |   |   |        |   |   |   |   |   |

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|                                                                                                                               |   | 2010   |       |   | 2009   |   |
|------------------------------------------------------------------------------------------------------------------------------------|--------|--------|------------|--------|--------|--------|
|                                                                                                                               |   |   |       |   |   |   |
| Vanguard 500 Index Fund Investor Shares                                                                                            |   | $      | 23,850,175 |   |   | $      | 21,068,811 |   |
| Vanguard Developed Markets Index Fund                                                                                              |   |   | -          |   |   |   | 9,266,662 |   |
| Vanguard Small-Cap Index Fund Investor Shares                                                                                      |   |   | 13,691,347 |   |   |   | 10,717,121 |   |
| Vanguard Wellington Fund Investor Shares                                                                                           |   |   | 18,732,097 |   |   |   | 17,852,185 |   |
| Nicor Inc. common stock                                                                                                            |   |   | 11,243,971 |   |   |   | 10,527,921 |   |
| VRST**                                                                                                                             |   |   | 58,278,962 |   |   |   | 55,352,811 |   |
|                                                                                                                               |   |   |       |   |   |   |   |   |
|  **  At December 31, 2010 and 2009, the contract values of the VRST were $55,984,047 and $54,156,185, respectively. |   |   |

|                                                                                                             |   | 2010   |       |   | 2009   |   |
|------------------------------------------------------------------------------------------------------------------|--------|--------|------------|--------|--------|--------|
| Investment income:                                                                                               |   |   |       |   |   |   |
|   Dividends on Nicor Inc. common stock                                                                 |   | $      | 996,602    |   |   | $      | 1,028,216 |   |
|   Net change in the market value of Nicor Inc. common stock                                            |   |   | 3,992,528  |   |   |   | 4,348,730 |   |
|   Distributions from the stable value fund                                                             |   |   | 3,318,253  |   |   |   | 3,368,741 |   |
|   Income from registered investment companies:                                                         |   |   |       |   |   |   |   |   |
| Distributions                                                                                                    |   |   | 4,013,629  |   |   |   | 3,409,839 |   |
| Net investment gain                                                                                              |   |   | 21,277,070 |   |   |   | 30,470,796 |   |
|   Other                                                                                                |   |   | 273,774    |   |   |   | 56,282 |   |
|                                                                                                             |   |   |       |   |   |   |   |   |
|                                                                                                             |   |   | 33,871,856 |   |   |   | 42,682,604 |   |
|                                                                                                             |   |   |       |   |   |   |   |   |
| Administrative expenses                                                                                          |   |   | (74,823    | )      |   |   | (50,566 | ) |
|                                                                                                             |   |   |       |   |   |   |   |   |
| Increase in the Master Trust’s net assets derived from investment activities                               |   | $      | 33,797,033 |   |   | $      | 42,632,038 |   |
|                                                                                                             |   |   |       |   |   |   |   |   |
| Plan’s interest in increase in the Master Trust’s net assets derived from investment activities |   | $      | 19,480,775 |   |   | $      | 25,037,915 |   |

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|                                        |   | Quoted prices in active markets |        |   | Significant observable inputs |   |        |   |   |
|---------------------------------------------|--------|---------------------------------|-------------|--------|-------------------------------|--------|-------------|--------|--------|
|                                        |   | (Level 1)                       |        |   | (Level 2)                     |   |        | Total  |   |
| December 31, 2010                           |   |                            |        |   |                          |   |        |   |   |
| Stable value fund                           |   | $                               | -           |   |                          | $      | 114,953,405 |   |   | $ | 114,953,405 |   |
| Nicor Inc. common stock                     |   |                            | 25,517,357  |   |                          |   | -           |   |   |   | 25,517,357 |   |
| Registered investment companies:            |   |                            |        |   |                          |   |        |   |   |   |   |   |
|    Bond funds                |   |                            | 19,383,836  |   |                          |   | -           |   |   |   | 19,383,836 |   |
|    Balanced funds            |   |                            | 48,317,671  |   |                          |   | -           |   |   |   | 48,317,671 |   |
|    Domestic stock funds      |   |                            | 107,993,203 |   |                          |   | -           |   |   |   | 107,993,203 |   |
|    International stock funds |   |                            | 20,704,462  |   |                          |   | -           |   |   |   | 20,704,462 |   |
|                                        |   | $                               | 221,916,529 |   |                          | $      | 114,953,405 |   |   | $ | 336,869,934 |   |
|                                        |   |                            |        |   |                          |   |        |   |   |   |   |   |

| December 31, 2009                           |   |   |        |   |   |   |        |   |   |
|---------------------------------------------|--------|--------|-------------|--------|--------|--------|-------------|--------|--------|
| Stable value fund                           |   | $      | -           |   |   | $      | 110,463,871 |   |   | $ | 110,463,871 |   |
| Nicor Inc. common stock                     |   |   | 23,437,407  |   |   |   | -           |   |   |   | 23,437,407 |   |
| Registered investment companies:            |   |   |        |   |   |   |        |   |   |   |   |   |
|    Bond funds                |   |   | 16,401,723  |   |   |   | -           |   |   |   | 16,401,723 |   |
|    Balanced funds            |   |   | 42,547,164  |   |   |   | -           |   |   |   | 42,547,164 |   |
|    Domestic stock funds      |   |   | 90,411,252  |   |   |   | -           |   |   |   | 90,411,252 |   |
|    International stock funds |   |   | 19,113,969  |   |   |   | -           |   |   |   | 19,113,969 |   |
|                                        |   | $      | 191,911,515 |   |   | $      | 110,463,871 |   |   | $ | 302,375,386 |   |

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Table of Contents

|                                                                            |   | 2010   |        |   | 2009   |   |
|---------------------------------------------------------------------------------|--------|--------|-------------|--------|--------|--------|
| Net assets available for benefits per the financial statements                  |   | $      | 192,951,973 |   |   | $      | 172,108,624 |   |
| Adjustment from fair value to contract value for the stable value fund     |   |   | 2,294,915   |   |   |   | 1,196,626 |   |
| Less:  Deemed distributions included as expense in the Form 5500 |   |   | 13,379      |   |   |   | 8,960 |   |
| Net assets available for benefits per Form 5500                                 |   | $      | 195,233,509 |   |   | $      | 173,296,290 |   |

|                                                                                                                                                   |   | 2010   |       |   | 2009   |   |
|--------------------------------------------------------------------------------------------------------------------------------------------------------|--------|--------|------------|--------|--------|--------|
| Net increase per the financial statements                                                                                                              |   | $      | 20,843,349 |   |   | $      | 28,978,592 |   |
| Adjustment from fair value to contract value for the stable value fund                                                                            |   |   | 1,098,289  |   |   |   | 1,196,626 |   |
| Less:  Transfers in per the financial statements                                                                                             |   |   | 172,950    |   |   |   | 328,173 |   |
|            Deemed distributions included in benefits paid to participants in the Form 5500 |   |   | 4,419      |   |   |   | 8,960 |   |
| Net income per Form 5500                                                                                                                               |   | $      | 21,764,269 |   |   | $      | 29,838,085 |   |

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Table of Contents

| Nicor Companies Savings Investment Plan                                                     |                                            |                      |                                                                                    |
|---------------------------------------------------------------------------------------------|-------------------------------------------------|---------------------------|-----------------------------------------------------------------------------------------|
|  Form 5500 - Schedule H, Part IV, Line 4(i) - Schedule of Assets (Held at End of Year) |                                            |                      |                                                                                    |
|  December 31, 2010                                                                     |                                            |                      |                                                                                    |
|                                                                                        |                                            |                      |                                                                                    |   |   |   |
|                                                                                        |                                            |                      |                                                                                    |   |   |   |
|                                                                                        |                                            |                      |                                                                                    |   |   |
| Identity of Issue, Borrower or Similar Party                                                |                                            | Description of Investment |                                                                                    | Current Value |   |
|                                                                                        |                                            |                      |                                                                                    |   |   |   |
|                                                                                        |                                            |                      |                                                                                    |   |   |   |
| (A)                                                                                         | Investments held in Master Trust, at fair value |                      | Various                                                                                 |   | $ | 191,131,284 |   |
|                                                                                        |                                            |                      |                                                                                    |   |   |   |   |
| (A)                                                                                         | Various participants                            |                      | Participant loans earning interest from 4.25% to 9.25%, maturing from 2011 through 2015 |   |   | 3,227,235 |   |
|                                                                                        |                                            |                      |                                                                                    |   |   |   |   |
|                                                                                        | Total                                           |                      |                                                                                    |   | $ | 194,358,519 |   |
|                                                                                        |                                            |                      |                                                                                    |   |   |   |   |
| (A)                                                                                         | Denotes party-in-interest investment            |                      |                                                                                    |   |   |   |   |

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Nicor Gas Thrift Plan

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Table of Contents

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

----

Table of Contents

| Nicor Gas Thrift Plan                                                      |   |
|----------------------------------------------------------------------------|--------|
| Statements of Net Assets Available for Benefits                            |   |
|                                                                       |   |   |   |   |   |   |
|                                                                       |   |   |   |   |   |   |
|                                                                       |   | December 31 |   |
|                                                                       |   | 2010 |   |   | 2009 |   |
| Assets:                                                                    |   |   |   |   |   |   |
| Participant-directed investments in Master                                 |   |   |   |   |   |   |
| Trust, at fair value                                                       |   | $ | 145,738,650 |   |   | $ | 132,742,608 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Receivables:                                                               |   |   |   |   |   |   |   |   |
| Notes receivable from participants                                         |   |   | 5,450,791 |   |   |   | 4,610,404 |   |
| Employer contributions                                                     |   |   | 372,257 |   |   |   | 334,887 |   |
| Participant contributions                                                  |   |   | 168,015 |   |   |   | 161,206 |   |
|                                                                       |   |   | 5,991,063 |   |   |   | 5,106,497 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Net assets available for benefits, at fair value                           |   |   | 151,729,713 |   |   |   | 137,849,105 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Adjustment from fair value to contract value for the stable value fund     |   |   | (2,231,733 | ) |   |   | (1,191,400 | ) |
|                                                                       |   |   |   |   |   |   |   |   |
| Net assets available for benefits                                          |   | $ | 149,497,980 |   |   | $ | 136,657,705 |   |
|                                                                       |   |   |   |   |   |   |   |   |
|                                                                       |   |   |   |   |   |   |   |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Statements of Changes in Net Assets Available for Benefits                 |   |
|                                                                       |   |   |   |   |   |   |   |   |
|                                                                       |   |   |   |   |   |   |   |   |
|                                                                       |   | Year ended December 31 |   |
|                                                                       |   |   | 2010 |   |   |   | 2009 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Net increase in Plan assets from investment activities of the Master Trust |   | $ | 14,316,258 |   |   | $ | 17,594,123 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Contributions:                                                             |   |   |   |   |   |   |   |   |
| Participant                                                                |   |   | 4,332,964 |   |   |   | 4,102,566 |   |
| Employer                                                                   |   |   | 2,027,041 |   |   |   | 1,947,267 |   |
|                                                                       |   |   | 6,360,005 |   |   |   | 6,049,833 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Interest income on notes receivable from participants                      |   |   | 269,327 |   |   |   | 312,225 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Benefits paid to participants                                              |   |   | (7,990,729 | ) |   |   | (5,828,076 | ) |
|                                                                       |   |   |   |   |   |   |   |   |
| Transfers out                                                              |   |   | (114,586 | ) |   |   | (328,173 | ) |
|                                                                       |   |   |   |   |   |   |   |   |
| Net increase                                                               |   |   | 12,840,275 |   |   |   | 17,799,932 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Net assets available for benefits at beginning of year                     |   |   | 136,657,705 |   |   |   | 118,857,773 |   |
|                                                                       |   |   |   |   |   |   |   |   |
| Net assets available for benefits at end of year                           |   | $ | 149,497,980 |   |   | $ | 136,657,705 |   |
|                                                                       |   |   |   |   |   |   |   |   |
|                                                                       |   |   |   |   |   |   |   |   |
| The accompanying notes are an integral part of these statements.           |   |   |   |   |   |   |   |   |

----

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1.  DESCRIPTION OF THE PLAN

----

Table of Contents

----

Table of Contents

----

Table of Contents

|                                                                                        |   | 2010   |        |   | 2009   |   |
|---------------------------------------------------------------------------------------------|--------|--------|-------------|--------|--------|--------|
| Assets:                                                                                     |   |   |        |   |   |   |
|   General investments (at fair value):                                            |   |   |        |   |   |   |
|     Stable value fund*                                                  |   | $      | 114,953,405 |   |   | $      | 110,463,871 |   |
|     Nicor Inc. common stock*                                            |   |   | 25,517,357  |   |   |   | 23,437,407 |   |
|     Registered investment companies*                                    |   |   | 196,399,172 |   |   |   | 168,474,108 |   |
|                                                                                        |   |   |        |   |   |   |   |   |
| Net assets in the Master Trust, at fair value                                               |   |   | 336,869,934 |   |   |   | 302,375,386 |   |
|                                                                                        |   |   |        |   |   |   |   |   |
| Adjustment from fair value to contract value for the stable value fund                 |   |   | (4,526,648  | )      |   |   | (2,388,026 | ) |
|                                                                                        |   |   |        |   |   |   |   |   |
| Net assets in the Master Trust                                                              |   | $      | 332,343,286 |   |   | $      | 299,987,360 |   |
|                                                                                        |   |   |        |   |   |   |   |   |
| Plan’s interest in the Master Trust’s net assets, at fair value            |   | $      | 145,738,650 |   |   | $      | 132,742,608 |   |
|                                                                                        |   |   |        |   |   |   |   |   |
| Plan’s percentage interest in the Master Trust’s net assets, at fair value |   |   | 43          | %      |   |   | 44 | % |
|                                                                                        |   |   |        |   |   |   |   |   |
|  *  Party-in-interest investments.                                           |   |   |        |   |   |   |   |   |

----

Table of Contents

|                                                                                                                               |   | 2010   |       |   | 2009   |   |
|------------------------------------------------------------------------------------------------------------------------------------|--------|--------|------------|--------|--------|--------|
|                                                                                                                               |   |   |       |   |   |   |
| Vanguard 500 Index Fund Investor Shares                                                                                            |   | $      | 16,726,504 |   |   | $      | 14,990,836 |   |
| Vanguard Small-Cap Index Fund Investor Shares                                                                                      |   |   | 11,330,307 |   |   |   | 8,846,820 |   |
| Vanguard Wellington Fund Investor Shares                                                                                           |   |   | 13,446,655 |   |   |   | 12,671,170 |   |
| Nicor Inc. common stock                                                                                                            |   |   | 14,273,386 |   |   |   | 12,909,486 |   |
| VRST**                                                                                                                             |   |   | 56,674,443 |   |   |   | 55,111,060 |   |
|                                                                                                                               |   |   |       |   |   |   |   |   |
|  **  At December 31, 2010 and 2009, the contract values of the VRST were $54,442,710 and $53,919,660, respectively. |   |   |

|                                                                                                             |   | 2010   |       |   | 2009   |   |
|------------------------------------------------------------------------------------------------------------------|--------|--------|------------|--------|--------|--------|
| Investment income:                                                                                               |   |   |       |   |   |   |
|   Dividends on Nicor Inc. common stock                                                                 |   | $      | 996,602    |   |   | $      | 1,028,216 |   |
|   Net change in the market value of Nicor Inc. common stock                                       |   |   | 3,992,528  |   |   |   | 4,348,730 |   |
|   Distributions from the stable value fund                                                             |   |   | 3,318,253  |   |   |   | 3,368,741 |   |
|   Income from registered investment companies:                                                         |   |   |       |   |   |   |   |   |
| Distributions                                                                                                    |   |   | 4,013,629  |   |   |   | 3,409,839 |   |
| Net investment gain                                                                                              |   |   | 21,277,070 |   |   |   | 30,470,796 |   |
|   Other                                                                                                |   |   | 273,774    |   |   |   | 56,282 |   |
|                                                                                                             |   |   |       |   |   |   |   |   |
|                                                                                                             |   |   | 33,871,856 |   |   |   | 42,682,604 |   |
|                                                                                                             |   |   |       |   |   |   |   |   |
| Administrative expenses                                                                                          |   |   | (74,823    | )      |   |   | (50,566 | ) |
|                                                                                                             |   |   |       |   |   |   |   |   |
| Increase in the Master Trust’s net assets derived from investment activities                          |   | $      | 33,797,033 |   |   | $      | 42,632,038 |   |
|                                                                                                             |   |   |       |   |   |   |   |   |
| Plan’s interest in increase in the Master Trust’s net assets derived from investment activities |   | $      | 14,316,258 |   |   | $      | 17,594,123 |   |

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|                                        |   | Quoted prices in active markets |        |   | Significant observable inputs |   |        |   |   |
|---------------------------------------------|--------|---------------------------------|-------------|--------|-------------------------------|--------|-------------|--------|--------|
|                                        |   | (Level 1)                       |        |   | (Level 2)                     |   |        | Total  |   |
| December 31, 2010                           |   |                            |        |   |                          |   |        |   |   |
| Stable value fund                           |   | $                               | -           |   |                          | $      | 114,953,405 |   |   | $ | 114,953,405 |   |
| Nicor Inc. common stock                     |   |                            | 25,517,357  |   |                          |   | -           |   |   |   | 25,517,357 |   |
| Registered investment companies:            |   |                            |        |   |                          |   |        |   |   |   |   |   |
|    Bond funds                |   |                            | 19,383,836  |   |                          |   | -           |   |   |   | 19,383,836 |   |
|    Balanced funds            |   |                            | 48,317,671  |   |                          |   | -           |   |   |   | 48,317,671 |   |
|    Domestic stock funds      |   |                            | 107,993,203 |   |                          |   | -           |   |   |   | 107,993,203 |   |
|    International stock funds |   |                            | 20,704,462  |   |                          |   | -           |   |   |   | 20,704,462 |   |
|                                        |   | $                               | 221,916,529 |   |                          | $      | 114,953,405 |   |   | $ | 336,869,934 |   |
|                                        |   |                            |        |   |                          |   |        |   |   |   |   |   |

| December 31, 2009                           |   |   |        |   |   |   |        |   |   |
|---------------------------------------------|--------|--------|-------------|--------|--------|--------|-------------|--------|--------|
| Stable value fund                           |   | $      | -           |   |   | $      | 110,463,871 |   |   | $ | 110,463,871 |   |
| Nicor Inc. common stock                     |   |   | 23,437,407  |   |   |   | -           |   |   |   | 23,437,407 |   |
| Registered investment companies:            |   |   |        |   |   |   |        |   |   |   |   |   |
|    Bond funds                |   |   | 16,401,723  |   |   |   | -           |   |   |   | 16,401,723 |   |
|    Balanced funds            |   |   | 42,547,164  |   |   |   | -           |   |   |   | 42,547,164 |   |
|    Domestic stock funds      |   |   | 90,411,252  |   |   |   | -           |   |   |   | 90,411,252 |   |
|    International stock funds |   |   | 19,113,969  |   |   |   | -           |   |   |   | 19,113,969 |   |
|                                        |   | $      | 191,911,515 |   |   | $      | 110,463,871 |   |   | $ | 302,375,386 |   |

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|                                                                            |   | 2010   |        |   | 2009   |   |
|---------------------------------------------------------------------------------|--------|--------|-------------|--------|--------|--------|
| Net assets available for benefits per the financial statements                  |   | $      | 149,497,980 |   |   | $      | 136,657,705 |   |
| Adjustment from fair value to contract value for the stable value fund     |   |   | 2,231,733   |   |   |   | 1,191,400 |   |
| Less:  Deemed distributions included as expense in the Form 5500 |   |   | 46,648      |   |   |   | 3,985 |   |
| Net assets available for benefits per Form 5500                                 |   | $      | 151,683,065 |   |   | $      | 137,845,120 |   |

|                                                                                             |   | 2010   |       |   | 2009   |   |
|--------------------------------------------------------------------------------------------------|--------|--------|------------|--------|--------|--------|
| Net increase per the financial statements                                                        |   | $      | 12,840,275 |   |   | $      | 17,799,932 |   |
| Adjustment from fair value to contract value for the stable value fund                      |   |   | 1,040,333  |   |   |   | 1,191,400 |   |
| Transfers out per the financial statements                                                       |   |   | 114,586    |   |   |   | 328,173 |   |
| Less:  Deemed distributions included in benefits paid to participants in the Form 5500 |   |   | 42,663     |   |   |   | - |   |
| Net income per Form 5500                                                                         |   | $      | 13,952,531 |   |   | $      | 19,319,505 |   |

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|  Nicor Gas Thrift Plan                                                           |                                            |                      |                                                                                    |
|---------------------------------------------------------------------------------------|-------------------------------------------------|---------------------------|-----------------------------------------------------------------------------------------|
| Form 5500 - Schedule H, Part IV, Line 4(i) - Schedule of Assets (Held at End of Year) |                                            |                      |                                                                                    |
|  December 31, 2010                                                               |                                            |                      |                                                                                    |
|                                                                                  |                                            |                      |                                                                                    |   |   |   |
|                                                                                  |                                            |                      |                                                                                    |   |   |   |
|  Identity of Issue, Borroweror Similar Party                                     |                                            | Description of Investment |                                                                                    | Current Value |   |
|                                                                                  |                                            |                      |                                                                                    |   |   |   |
|                                                                                  |                                            |                      |                                                                                    |   |   |   |
| (A)                                                                                   | Investments held in Master Trust, at fair value |                      | Various                                                                                 |   | $ | 145,738,650 |   |
|                                                                                  |                                            |                      |                                                                                    |   |   |   |   |
| (A)                                                                                   | Various participants                            |                      | Participant loans earning interest from 4.25% to 9.25%, maturing from 2011 through 2016 |   |   | 5,404,143 |   |
|                                                                                  |                                            |                      |                                                                                    |   |   |   |   |
|                                                                                  | Total                                           |                      |                                                                                    |   | $ | 151,142,793 |   |
|                                                                                  |                                            |                      |                                                                                    |   |   |   |   |
| (A)                                                                                   | Denotes party-in-interest investment            |                      |                                                                                    |   |   |   |   |

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Signature

|                      |   | Nicor Companies Savings Investment Plan    |   |
|---------------------------|--------|--------------------------------------------|--------|
|                      |   | and Nicor Gas Thrift Plan                  |   |
|                      |   |                                       |   |
| Date:  June 15, 2011 |   | /s/ REBECCA C. MEGGESIN                    |   |
|                      |   | Rebecca C. Meggesin                        |   |
|                      |   | Plan Administrator and                     |   |
|                      |   | Vice President Human Resources, Nicor Inc. |   |

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Exhibit Index

| Exhibit |   |                                                                                                          |
|---------|--------|---------------------------------------------------------------------------------------------------------------|
| Number  |   | Description of Document                                                                                       |
|    |   |                                                                                                          |
| 23.01   |   | Consent of Independent Registered Public Accounting Firm – Nicor Companies Savings Investment Plan |
|    |   |                                                                                                          |
| 23.02   |   | Consent of Independent Registered Public Accounting Firm – Nicor Gas Thrift Plan                        |
|    |   |                                                                                                          |

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