EXHIBIT 12

# Statement Regarding
Computation of Ratios



The
ratios of income to fixed charges have been computed on the basis of the total enterprise
(as defined by the Commission) by dividing income before fixed charges and income taxes by
fixed charges. Fixed charges consist of interest expense on all long-term and short-term
borrowings, excluding or including interest on deposits as indicated below. The
computations of other ratios are evident from the information presented in this Form 10-Q
and the Corporations 2002 Annual Report.

# Bank One Corporation and
Subsidiaries

# COMPUTATIONS OF
CONSOLIDATED RATIOS OF EARNINGS TO FIXED CHARGES

|(In millions, except ratios)                      | Six Months Ended
June 30, 2003 | Year Ended
2002 | Year Ended
2001 | Year Ended
2000 (1) | Year Ended
1999
|------------------------------------------------- | ------------------------------ | --------------- | --------------- | ------------------- | ---------------
|EXCLUDING INTEREST ON DEPOSITS:                   |                                |                 |                 |                     |                
|Pretax income (loss) from continuing operations   |                                |                 | $               | 2,383               |                
|Earnings (loss) from unconsolidated entities      |                                |                
|under the equity method of accounting             |                                |                 |                 | 61                  |                
|Fixed charges, excluding capitalized interest     |                                |                 |                 | 1,336               |                
|                                                  |                                |                 |                 |                     |                
|Adjusted pretax earnings base                     |                                |                 |                 | 3,780               |                
|                                                  |                                |                
|Interest, excluding interest on deposits          |                                |                 |                 | 1,284               |                
|Rental factor                                     |                                |                 |                 | 52                  |                
|Capitalized interest                              |                                |                 |                 | 1                   |                
|                                                  |                                |                 |                 |                     |                
|Fixed charges                                     |                                |                 |                 | 1,337               |                
|Consolidated ratios of earnings to fixed charges, |                                |                
|excluding interest on deposits                    |                                |                 |                 | 2.8x                |                
|                                                  |                                |                
|INCLUDING INTEREST ON DEPOSITS:                   |                                |                
|Pretax income (loss) from continuing operations   |                                |                 | $               | 2,383               |                
|Earnings (loss) from unconsolidated entities      |                                |                
|under the equity method of accounting             |                                |                 |                 | 61                  |                
|Fixed charges, excluding capitalized interest     |                                |                 |                 | 2,418               |                
|                                                  |                                |                 |                 |                     |                
|Adjusted pretax earnings base                     |                                |                 |                 | 4,862               |                
|                                                  |                                |                
|Interest, including interest on deposits          |                                |                 |                 | 2,366               |                
|Rental factor                                     |                                |                 |                 | 52                  |                
|Capitalized interest                              |                                |                 |                 | 1                   |                
|                                                  |                                |                 |                 |                     |                
|Fixed charges                                     |                                |                 |                 | 2,419               |                
|Consolidated ratios of earnings to fixed charges, |                                |                
|including interest on deposits                    |                                |                 |                 | 2.0x                |                
|                                                  |                                |                 |                 |                     |                

| | (1) | Results for the year ended December 31, 2000 were insufficient to cover fixed
               charges. The coverage deficiency was approximately $1.2 billion.
| | --- | -------------------------------------------------------------------------------------------------------------------------------------------------------------

73

---