13G Filing: Viking Global and United States Steel Corp (X)

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Page 2 of 21 – SEC Filing

Schedule 13G PAGE 2 of 21

CUSIP No. 912909108
_____________________________________________________________________________
(1) NAME OF REPORTING PERSON
S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
Viking Global Investors LP
_____________________________________________________________________________
(2) CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
(a) [ ]
(b) [x]
_____________________________________________________________________________
(3) SEC USE ONLY

_____________________________________________________________________________
(4) CITIZENSHIP OR PLACE OF ORGANIZATION
Delaware
_____________________________________________________________________________

NUMBER OF (5) SOLE VOTING POWER
0
SHARES ______________________________________________________________

BENEFICIALLY (6) SHARED VOTING POWER
9,662,352
OWNED BY ______________________________________________________________

EACH (7) SOLE DISPOSITIVE POWER
0
REPORTING ______________________________________________________________

PERSON WITH (8) SHARED DISPOSITIVE POWER
9,662,352
_____________________________________________________________________________
(9) AGGREGATE AMOUNT BENEFICIALLY OWNED
BY EACH REPORTING PERSON
9,662,352
_____________________________________________________________________________
(10) CHECK BOX IF THE AGGREGATE AMOUNT
IN ROW (9) EXCLUDES CERTAIN SHARES [ ]
_____________________________________________________________________________
(11) PERCENT OF CLASS REPRESENTED
BY AMOUNT IN ROW (9)
5.5%
_____________________________________________________________________________
(12) TYPE OF REPORTING PERSON
PN
_____________________________________________________________________________

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