Report of Independent Registered Public Accounting Firm

To the Shareholders of the Funds and Board of Trustees of MainStay Funds
Trust:

In planning and performing our audits of the financial statements of MainStay
CBRE Global Infrastructure Fund, MainStay CBRE Real Estate Fund, MainStay
MacKay Intermediate Tax Free Bond Fund, MainStay MacKay Short Term
Municipal Fund, MainStay Defensive ETF Allocation Fund, MainStay Conservative
ETF Allocation Fund, MainStay Moderate ETF Allocation Fund, MainStay Growth
ETF Allocation Fund, and MainStay Equity ETF Allocation Fund, nine of the
funds comprising MainStay Funds Trust (the Funds), as of and for the year or
period ended April 30, 2021, in accordance with the standards of the Public
Company Accounting Oversight Board (United States), we considered the Funds'
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 Funds' internal control
over financial reporting. Accordingly, we express no such opinion.

Management of the Funds 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 the 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 Funds' annual or interim financial
statements will not be prevented or detected on a timely basis.

KPMG LLP is a Delaware limited liability partnership and the U.S. member
firm of the KPMG network of independent member firms affiliated with KPMG
International Cooperative ("KPMG International"), a Swiss entity.

Our consideration of the Funds' 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 Public Company
Accounting Oversight Board (United States). However, we noted no deficiencies
in the Funds' internal control over financial reporting and its operation,
including controls over safeguarding securities that we consider to be a
material weakness as defined above as of April 30, 2021.

This report is intended solely for the information and use of management
and the Board of Trustees of MainStay Funds Trust 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/ KPMG LLP

Philadelphia, Pennsylvania
June 24, 2021