REPORT OF INDEPENDENT REGISTERED
PUBLIC ACCOUNTING FIRM

To the shareholders and the Board of Trustees of
Blackstone Alternative Alpha Master Fund and Subsidiary

In planning and performing our audit of the consolidated
financial statements of Blackstone Alternative Alpha
Master Fund and Subsidiary (the "Master Fund") as of and
for the year ended March 31, 2020, in accordance with the
standards of the Public Company Accounting Oversight
Board (United States) (PCAOB), we considered the Master
Fund's internal control over financial reporting, including
controls over safeguarding securities, as a basis for
designing our auditing procedures for the purpose of
expressing our opinion on the financial statements and to
comply with the requirements of Form N-CEN, but not for
the purpose of expressing an opinion on the effectiveness
of the Master Fund's internal control over financial
reporting. Accordingly, we express no such opinion.

The management of the Master Fund is responsible for
establishing and maintaining effective internal control over
financial reporting. In fulfilling this responsibility,
estimates and judgments by management are required to
assess the expected benefits and related costs of controls. A
fund's internal control over financial reporting is a process
designed to provide reasonable assurance regarding the
reliability of financial reporting and the preparation of
financial statements for external purposes in accordance
with generally accepted accounting principles. A fund's
internal control over financial reporting includes those
policies and procedures that (1) pertain to the maintenance
of records that, in reasonable detail, accurately and fairly
reflect the transactions and dispositions of the assets of the
fund; (2) provide reasonable assurance that transactions are
recorded as necessary to permit preparation of financial
statements in accordance with generally accepted
accounting principles, and that receipts and expenditures of
the fund are being made only in accordance with
authorizations of management and directors of the fund;
and (3) provide reasonable assurance regarding prevention
or timely detection of unauthorized acquisition, use, or
disposition of a fund's assets that could have a material
effect on the financial statements.

Because of its inherent limitations, internal control over
financial reporting may not prevent or detect misstatements.
Also, projections of any evaluation of effectiveness to
future periods are subject to the risk that controls may
become inadequate because of changes in conditions or that
the degree of compliance with the policies or procedures
may deteriorate.

A deficiency in internal control over financial reporting
exists when the design or operation of a control does not
allow management or employees, in the normal course of
performing their assigned functions, to prevent or detect
misstatements on a timely basis. A material weakness is a
deficiency, or a combination of deficiencies, in internal
control over financial reporting, such that there is a
reasonable possibility that a material misstatement of the
fund's annual or interim financial statements will not be
prevented or detected on a timely basis.

Our consideration of the Master Fund's internal control
over financial reporting was for the limited purpose
described in the first paragraph and would not necessarily
disclose all deficiencies in internal control that might be
material weaknesses under standards established by the
PCAOB. However, we noted no deficiencies in the Master
Fund's internal control over financial reporting and its
operation, including controls for safeguarding securities,
that we consider to be a material weakness, as defined
above, as of March 31, 2020.

This report is intended solely for the information and use of
management and the Board of Trustees of the Master Fund
and the Securities and Exchange Commission and is not
intended to be and should not be used by anyone other than
these specified parties.


/s/ Deloitte & Touche LLP
New York, New York
May 26, 2020