REPORT OF INDEPENDENT REGISTERED PUBLIC
ACCOUNTING FIRM
To the Board of Trustees of MFS Series Trust XIV and the
Shareholders of MFS Institutional Money Market Portfolio:
In planning and performing our audit of the financial
statements of MFS Institutional Money Market Portfolio (a
series of MFS Series Trust XIV) (the Fund) as of and for the
year ended August 31, 2020, in accordance with the standards
of the Public Company Accounting Oversight Board (United
States), 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 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 of the fund
and trustees of the trust; 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 a fund'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 Public Company Accounting
Oversight Board (United States).  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 August 31, 2020.
This report is intended solely for the information and use of
management, the Board of Trustees of MFS Series Trust XIV
and the Securities and Exchange Commission and is not
intended to be and should not be used by anyone other than
these specified parties.


Boston, Massachusetts
October 19, 2020