Report of Independent Registered Public Accounting Firm

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

In planning and performing our audits of the financial statements of
The MainStay Funds (the Funds), comprised of the MainStay WMC
Enduring Capital Fund (formerly MainStay MacKay Common Stock Fund),
MainStay MacKay Convertible Fund, MainStay Candriam Emerging Markets
Debt Fund, MainStay MacKay U.S. Infrastructure Bond Fund
(formerly MainStay MacKay Infrastructure Bond Fund), MainStay MacKay
High Yield Corporate Bond Fund, MainStay Income Builder Fund,
MainStay MacKay International Equity Fund, MainStay Winslow Large
Cap Growth Fund, MainStay WMC Value Fund (formerly MainStay MAP
Equity Fund), MainStay Money Market Fund, MainStay MacKay Tax Free
Bond Fund, and MainStay Strategic Bond Fund (formerly MainStay MacKay
Unconstrained Bond Fund) 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 The MainStay Funds 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