REPORT OF INDEPENDENT REGISTERED PUBLIC
ACCOUNTING FIRM

To the Investors of Master Small Cap Index Series and the
Board of Directors of Quantitative Master Series LLC:

In planning and performing our audit of the financial statements
of Master Small Cap Index Series of Quantitative Master Series
LLC (the "Fund") as of and for the year ended December 31,
2019, in accordance with the standards of the Public Company
Accounting Oversight Board (United States) (PCAOB), we
considered the 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 Fund's
internal control over financial reporting. Accordingly, we
express no such opinion.

The management of the 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 company'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
company'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 company; (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
company are being made only in accordance with
authorizations of management and directors of the company;
and (3) provide reasonable assurance regarding prevention or
timely detection of unauthorized acquisition, use, or disposition
of a company'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 company's annual or interim
financial statements will not be prevented or detected on a
timely basis.

Our consideration of the 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 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 December 31, 2019.

This report is intended solely for the information and use of
management and the Board of Directors of the 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.

Deloitte & Touche LLP
Boston, Massachusetts
February 24, 2020