<Page>
EXHIBIT 12
COMPUTATION OF RATIO OF INCOME
FROM CONTINUING OPERATIONS TO FIXED CHARGES
(UNAUDITED)
<Table>
<Caption>
(Dollars in millions)
For Six Months Ended
----------------------------
June 30, 2003 June 30, 2002
------------- -------------
Income from continuing operations
before income taxes (1) $ 4,442 $ 2,408
Add: Fixed charges, excluding
capitalized interest 571 629
------------ ------------
Income as adjusted before income taxes $ 5,013 $ 3,037
============ ============
Fixed charges:
Interest expense $ 343 $ 399
Capitalized interest 9 19
Portion of rental expense representative of
interest 228 230
------------ ------------
Total fixed charges $ 580 $ 648
============ ============
Ratio of income from continuing 8.64 4.69
operations to fixed charges
</Table>
(1) Income from continuing operations before income taxes excludes (a)
amortization of capitalized interest and (b) the company's share in the income
and losses of less-than-fifty percent-owned affiliates.
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<Page>
SEGMENT INFORMATION - ON CONTINUING OPERATIONS BASIS (UNAUDITED)
<Table>
<Caption>
Hardware Segments
------------------------------------------------
Personal
Global Systems Systems Technology
(Dollars in millions) Services Group Group Group
- ----------------------------------------------------------------------------------------------------------
THREE MONTHS ENDED JUNE 30, 2003:
External revenue $ 10,635 $ 3,221 $ 2,723 $ 659
Internal revenue $ 695 182 44 237
------------- ------------- ------------- -------------
Total revenue $ 11,330 $ 3,403 $ 2,767 $ 896
============= ============= ============= =============
Pre-tax income (loss) $ 1,168 $ 396 $ (8) $ (111)
============= ============= ============= =============
Revenue year-to-year change 20.5% 10.0% (2.3)% (25.5)%
Pre-tax income year-to-year change 65.4% 117.6% 77.1% 88.2%
Pre-tax income margin 10.3% 11.6% (0.3)% (12.4)%
THREE MONTHS ENDED JUNE 30, 2002:
External revenue $ 8,661 $ 2,934 $ 2,800 $ 1,003
Internal revenue 741 160 33 199
------------- ------------- ------------- -------------
Total revenue $ 9,402 $ 3,094 $ 2,833 $ 1,202
============= ============= ============= =============
Pre-tax income (loss) $ 706 $ 182 $ (35) $ (943)
============= ============= ============= =============
Pre-tax income margin 7.5% 5.9% (1.2)% (78.5)%
</Table>
RECONCILIATIONS TO IBM AS REPORTED:
<Table>
<Caption>
Three Months Ended Three Months Ended
(Dollars in millions) June 30, 2003 June 30, 2002
------------- -------------
Revenue:
Total reportable segments $ 23,473 $ 21,347
Eliminations/other (1,842) (1,696)
----------------- -----------------
Total IBM Consolidated $ 21,631 $ 19,651
================= =================
Pretax income:
Total reportable segments $ 2,504 $ 979
Eliminations/other (38) (384)
----------------- -----------------
Total IBM Consolidated $ 2,466 $ 595
================= =================
</Table>
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<Page>
<Table>
<Caption>
Global Enterprise Total
(Dollars in millions) Software Financing Investments Segments
- -----------------------------------------------------------------------------------------------------------
THREE MONTHS ENDED JUNE 30, 2003:
External revenue $ 3,471 $ 681 $ 227 $ 21,617
Internal revenue 390 307 1 1,856
------------- ------------- ------------- -------------
Total revenue $ 3,861 $ 988 $ 228 $ 23,473
============= ============= ============= =============
Pre-tax income (loss) $ 850 $ 296 $ (87) $ 2,504
============= ============= ============= =============
Revenue year-to-year change 7.8% (2.3)% 1.8% 10.0%
Pre-tax income year-to-year change (6.9)% 24.9% (7.4)% 155.8%
Pre-tax income margin 22.0% 30.0% (38.2)% 10.7%
THREE MONTHS ENDED JUNE 30, 2002:
External revenue $ 3,266 $ 818 $ 223 $ 19,705
Internal revenue 315 193 1 1,642
------------- ------------- ------------- -------------
Total revenue $ 3,581 $ 1,011 $ 224 $ 21,347
============= ============= ============= =============
Pre-tax income (loss) $ 913 $ 237 $ (81) $ 979
============= ============= ============= =============
Pre-tax income margin 25.5% 23.4% (36.2)% 4.6%
</Table>
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<Page>
SEGMENT INFORMATION - ON CONTINUING OPERATIONS BASIS (UNAUDITED)
<Table>
<Caption>
Hardware Segments
-----------------------------------------------
Personal
Global Systems Systems Technology
(Dollars in millions) Services Group Group Group
- --------------------------------------------------------------------------------------------------------
SIX MONTHS ENDED JUNE 30, 2003:
External revenue $ 20,804 $ 5,867 $ 5,113 $ 1,401
Internal revenue 1,394 362 80 411
------------ ------------- ------------- --------------
Total revenue $ 22,198 $ 6,229 $ 5,193 $ 1,812
============ ============= ============= ==============
Pre-tax income (loss) $ 2,151 $ 591 $ (77) $ (122)
============ ============= ============= ==============
Revenue year-to-year change 21.5% 8.4% (3.1)% (23.5)%
Pre-tax income year-to-year change 20.9% 64.6% (356.7)% 88.7%
Pre-tax income margin 9.7% 9.5% (1.5)% (6.7)%
SIX MONTHS ENDED JUNE 30, 2002:
External revenue $ 16,890 $ 5,418 $ 5,311 $ 1,933
Internal revenue 1,381 326 46 435
------------ ------------- ------------- --------------
Total revenue $ 18,271 $ 5,744 $ 5,357 $ 2,368
============ ============= ============= ==============
Pre-tax income (loss) $ 1,779 $ 359 $ 30 $ (1,082)
============ ============= ============= ==============
Pre-tax income margin 9.7% 6.3% 0.6% (45.7)%
</Table>
RECONCILIATIONS TO IBM AS REPORTED:
<Table>
<Caption>
Six Months Ended Six Months Ended
(Dollars in millions) June 30, 2003 June 30, 2002
---------------- ----------------
Revenue:
Total reportable segments $ 45,263 $ 40,866
Eliminations/other (3,567) (3,185)
------------ -------------
Total IBM Consolidated $ 41,696 $ 37,681
============ =============
Pretax income:
Total reportable segments $ 4,447 $ 2,884
Eliminations/other - (476)
------------ -------------
Total IBM Consolidated $ 4,447 $ 2,408
============ =============
</Table>
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<Page>
<Table>
<Caption>
Global Enterprise Total
(Dollars in millions) Software Financing Investments Segments
- ---------------------------------------------------------------------------------------------------------
SIX MONTHS ENDED JUNE 30, 2003:
External revenue $ 6,600 $ 1,382 $ 468 $ 41,635
Internal revenue 777 602 2 3,628
------------- ------------- ------------- -------------
Total revenue $ 7,377 $ 1,984 $ 470 $ 45,263
============= ============= ============= =============
Pre-tax income (loss) $ 1,489 $ 569 $ (154) $ 4,447
============= ============= ============= =============
Revenue year-to-year change 10.0% 1.0% 3.1% 10.8%
Pre-tax income year-to-year change 1.1% 24.0% (14.9)% 54.2%
Pre-tax income margin 20.2% 28.7% (32.8)% 9.8%
SIX MONTHS ENDED JUNE 30, 2002:
External revenue $ 6,163 $ 1,586 $ 454 $ 37,755
Internal revenue 542 379 2 3,111
------------- ------------- ------------- -------------
Total revenue $ 6,705 $ 1,965 $ 456 $ 40,866
============= ============= ============= =============
Pre-tax income (loss) $ 1,473 $ 459 $ (134) $ 2,884
============= ============= ============= =============
Pre-tax income margin 22.0% 23.4% (29.4)% 7.1%
</Table>
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