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 Balanced Fund, MainStay MacKay California Tax Free
Opportunities Fund, MainStay Conservative Allocation Fund, MainStay
WMC Growth Fund (formerly MainStay MacKay Growth Fund), MainStay
Epoch Capital Growth Fund, MainStay Epoch Global Equity Yield Fund,
MainStay Epoch International Choice Fund, MainStay Epoch U.S.
Equity Yield Fund, MainStay WMC Small Companies Fund (formerly
MainStay MacKay Small Cap Core Fund), MainStay Floating Rate Fund,
MainStay Growth Allocation Fund, MainStay MacKay High Yield
Municipal Bond Fund, MainStay Short Term Bond Fund, MainStay WMC
International Research Equity Fund (formerly MainStay MacKay
International Opportunities Fund), MainStay Moderate Allocation
Fund, MainStay Equity Allocation Fund, MainStay MacKay New York
Tax Free Opportunities Fund, MainStay MacKay S&P 500 Index Fund,
MainStay MacKay Short Duration High Yield Fund, MainStay MacKay
Total Return Bond Fund, MainStay Candriam Emerging Markets Equity
Fund, and MainStay U.S. Government Liquidity Fund, twenty-two of
the funds comprising MainStay Funds Trust (the Funds), as of and
for the year ended October 31, 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.

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 October 31, 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
December 23, 2021