Report of Independent Registered Public Accounting Firm

To the Shareholders and Board of Trustees of
Pioneer Series Trust VI:

In planning and performing our audits of the financial statements of Pioneer
Flexible Opportunities Fund, and Pioneer Floating Rate Fund (the "Portfolios")
(two portfolios constituting Pioneer Series Trust VI) as of and for the year
ended October 31, 2018, in accordance with the standards of the Public Company
Accounting Oversight Board (United States), we considered the Portfolios'
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 Portfolios' internal control
over financial reporting.  Accordingly, we express no such opinion.

The management of the Portfolios 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 Portfolios' 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 Portfolios' 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, 2018.

This report is intended solely for the information and use of management and
the Board of Trustees of Pioneer Series Trust VI, 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/ ERNST& YOUNG LLP

Boston, Massachusetts
December 21, 2018