<TABLE> <S> <C>

<PAGE>

<ARTICLE> UT
<LEGEND> This schedule contains summary financial information extracted from the
Consolidated Balance Sheet and Statement of Consolidated Capitalization as of
June 30, 1999 and the related Statement of Consolidated Operations, Retained
Earnings and Cash Flows for the six months ended June 30, 1999 and is qualified
in its entirety by reference to such financial statements.
</LEGEND>
<CIK>      0000918040
<NAME>     Unicom Corporation
<MULTIPLIER> 1,000

<S>                             <C>
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1999
<PERIOD-START>                             JAN-01-1999
<PERIOD-END>                               JUN-30-1999
<BOOK-VALUE>                                  PER-BOOK
<TOTAL-NET-UTILITY-PLANT>                   13,439,135
<OTHER-PROPERTY-AND-INVEST>                  2,762,947
<TOTAL-CURRENT-ASSETS>                       3,290,645
<TOTAL-DEFERRED-CHARGES>                             0<F1>
<OTHER-ASSETS>                               4,503,972
<TOTAL-ASSETS>                              23,996,699
<COMMON>                                     4,955,090
<CAPITAL-SURPLUS-PAID-IN>                            0
<RETAINED-EARNINGS>                            156,743
<TOTAL-COMMON-STOCKHOLDERS-EQ>               5,101,309<F2>
<PREFERRED-MANDATORY>                                0<F3>
<PREFERRED>                                      1,836<F3>
<LONG-TERM-DEBT-NET>                         7,374,057<F4>
<SHORT-TERM-NOTES>                                   0<F1>
<LONG-TERM-NOTES-PAYABLE>                            0<F4>
<COMMERCIAL-PAPER-OBLIGATIONS>                       0<F1>
<LONG-TERM-DEBT-CURRENT-PORT>                  910,642
<PREFERRED-STOCK-CURRENT>                      142,113<F3>
<CAPITAL-LEASE-OBLIGATIONS>                    257,611
<LEASES-CURRENT>                               170,014
<OTHER-ITEMS-CAPITAL-AND-LIAB>              10,039,117<F5>
<TOT-CAPITALIZATION-AND-LIAB>               23,996,699
<GROSS-OPERATING-REVENUE>                    3,223,518
<INCOME-TAX-EXPENSE>                           113,437<F6>
<OTHER-OPERATING-EXPENSES>                   2,630,728
<TOTAL-OPERATING-EXPENSES>                   2,740,297
<OPERATING-INCOME-LOSS>                        483,221
<OTHER-INCOME-NET>                             (4,087)<F6><F7><F8>
<INCOME-BEFORE-INTEREST-EXPEN>                 475,266
<TOTAL-INTEREST-EXPENSE>                       286,231
<NET-INCOME>                                   189,035
<PREFERRED-STOCK-DIVIDENDS>                          0<F7>
<EARNINGS-AVAILABLE-FOR-COMM>                  189,035
<COMMON-STOCK-DIVIDENDS>                       173,781
<TOTAL-INTEREST-ON-BONDS>                            0<F9>
<CASH-FLOW-OPERATIONS>                         780,056
<EPS-BASIC>                                       0.87
<EPS-DILUTED>                                     0.87
<FN>
<F1> This item is not disclosed as a separate line item on the Consolidated
     Balance Sheet.
<F2> Includes deductions of $429 thousand for preference stock expense of ComEd
     and $10,095 thousand for treasury stock.
<F3> Preferred and preference stocks of ComEd.
<F4> $3,925,936 thousand of notes, guaranteed senior notes and transitional
     trust notes are included in LONG-TERM-DEBT-NET.
<F5> Includes $350,000 thousand of ComEd-obligated mandatorily redeemable
     preferred securities of subsidiary trusts holding solely ComEd's
     subordinated debt securities.
<F6> Income tax expense of $3,868 thousand related to nonoperating activities is
     included in INCOME-TAX-EXPENSE.
<F7> A $18,340 thousand provision for preferred and preference stock dividends
     of ComEd and a $14,855 thousand provision for preferred securities
     dividends of subsidiary trusts holding solely ComEd's subordinated debt
     securities are included in OTHER-INCOME-NET.
<F8> Includes an extraordinary loss of $27,576 thousand related to the early
     redemptions and the tender offer of first mortgage bonds and sinking fund
     debentures in the first quarter of 1999.
<F9> This item is not disclosed as a separate line item on the Statement of
     Consolidated Operations.
</FN>


</TABLE>