Ownership Submission
FORM 3
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  BlackRock Inc.
2. Date of Event Requiring Statement (Month/Day/Year)
12/10/2013
3. Issuer Name and Ticker or Trading Symbol
BlackRock Alternatives Allocation Master Portfolio LLC [BAAPMASTER]
(Last)
(First)
(Middle)
55 EAST 52ND STREET
4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director __X__ 10% Owner
_____ Officer (give title below) __X__ Other (specify below)
Affil. of Investment Adviser
5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

NEW YORK, NY 10055
6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)
2. Amount of Securities Beneficially Owned
(Instr. 4)
3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)
4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Limited Liability Company Units 2,963,740.112 (1)
I
See Footnote (1)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)
2. Date Exercisable and Expiration Date
(Month/Day/Year)
3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)
4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)
6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
BlackRock Inc.
55 EAST 52ND STREET
NEW YORK, NY 10055
    X   Affil. of Investment Adviser

Signatures

/s/ Neal Andrews, Managing Director 12/12/2013
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Ownership is by BlackRock Holdco 2, Inc. ("Holdco"), a wholly owned subsidiary of the Reporting Person, and BlackRock Advisors, LLC ("Advisors"), also a wholly owned subsidiary of the Reporting Person. Holdco and Advisors acquired units as a result of a liquidating distribution by BlackRock Alternatives Allocation FB Portfolio LLC ("BAAP FB"). Amount of units received by Holdco and Advisors based on Holdco's and Advisors' respective pro rata ownership of BAAP FB.

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