EX-99.19a-1

MFS® Intermediate High Income Fund

P.O. Box 43078

Providence, RI 02940-3078

Notice to shareholders Source of distribution

Distribution period

May-2026

Distribution amount per share

$0.01424

The following table sets forth the estimated amounts of the current distribution and the cumulative distributions paid this fiscal year to date from the following sources: net investment income, net realized short-term capital gains, net realized long-term capital gains and return of capital or other capital source. The fund’s fiscal year begins each December 1st. All amounts are expressed per common share.

 

 

% Breakdown

Total cumulative

% Breakdown of the total

 

Current

of current

distributions for the

cumulative distributions

 

distribution

distribution

fiscal year to date

for the fiscal year to date

Net Investment Income

0.00897

63%

0.06240

72%

Net Realized ST Cap Gains

0.00000

0%

0.00000

0%

Net Realized LT Cap Gains

0.00000

0%

0.00000

0%

Return of Capital or

 

 

 

 

Other Capital Source

0.00527

37%

0.02427

28%

Total (per common share)

0.01424

100%

0.08667

100%

Average annual total return (in relation to NAV) for the five years ended 4-30-2026

3.54%

Annualized current distribution rate expressed as a percentage of month end NAV as of 4-30-2026

9.55%

Cumulative total return (in relation to NAV) for the fiscal year through 4-30-2026

1.55%

Cumulative fiscal year distributions as a percentage of NAV as of 4-30-2026

4.84%

You should not draw any conclusions about the fund's investment performance from the amount of this distribution or from the terms of the fund's managed distribution plan.

The fund estimates that it has distributed more than its income and capital gains; therefore, a portion of your distribution may be a return of capital. A return of capital may occur, for example, when some or all of the money that you invested in the fund is paid back to you. A return of capital distribution does not necessarily reflect the fund's investment performance and should not be confused with "yield" or "income."

The amounts and sources of distributions reported in this notice are only estimates and are not being provided for tax-reporting purposes. The actual amounts and sources of the amounts for tax-reporting purposes will depend upon the fund's investment experience during the remainder of its fiscal year and may be subject to changes based on tax regulations. The fund will send you a Form 1099-DIV for the calendar year that will tell you how to report these distributions for federal income tax purposes. If you have any questions regarding this information, please call our fund service department at 1-800-637-2304 any business day from 9 a.m. to 5 p.m. Eastern time.

CIHSN-0526

MFS® Intermediate High Income Fund

P.O. Box 43078

Providence, RI 02940-3078

Notice to shareholders Source of distribution

Distribution period

April-2026

Distribution amount per share

$0.01416

The following table sets forth the estimated amounts of the current distribution and the cumulative distributions paid this fiscal year to date from the following sources: net investment income, net realized short-term capital gains, net realized long-term capital gains and return of capital or other capital source. The fund’s fiscal year begins each December 1st. All amounts are expressed per common share.

 

 

% Breakdown

Total cumulative

% Breakdown of the total

 

Current

of current

distributions for the

cumulative distributions

 

distribution

distribution

fiscal year to date

for the fiscal year to date

Net Investment Income

0.01204

85%

0.05360

74%

Net Realized ST Cap Gains

0.00000

0%

0.00000

0%

Net Realized LT Cap Gains

0.00000

0%

0.00000

0%

Return of Capital or

 

 

 

 

Other Capital Source

0.00212

15%

0.01883

26%

Total (per common share)

0.01416

100%

0.07243

100%

Average annual total return (in relation to NAV) for the five years ended 3-31-2026

3.37%

Annualized current distribution rate expressed as a percentage of month end NAV as of 3-31-2026

9.60%

Cumulative total return (in relation to NAV) for the fiscal year through 3-31-2026

-0.45%

Cumulative fiscal year distributions as a percentage of NAV as of 3-31-2026

4.09%

You should not draw any conclusions about the fund's investment performance from the amount of this distribution or from the terms of the fund's managed distribution plan.

The fund estimates that it has distributed more than its income and capital gains; therefore, a portion of your distribution may be a return of capital. A return of capital may occur, for example, when some or all of the money that you invested in the fund is paid back to you. A return of capital distribution does not necessarily reflect the fund's investment performance and should not be confused with "yield" or "income."

The amounts and sources of distributions reported in this notice are only estimates and are not being provided for tax-reporting purposes. The actual amounts and sources of the amounts for tax-reporting purposes will depend upon the fund's investment experience during the remainder of its fiscal year and may be subject to changes based on tax regulations. The fund will send you a Form 1099-DIV for the calendar year that will tell you how to report these distributions for federal income tax purposes. If you have any questions regarding this information, please call our fund service department at 1-800-637-2304 any business day from 9 a.m. to 5 p.m. Eastern time.

CIHSN-0426

MFS® Intermediate High Income Fund

P.O. Box 43078

Providence, RI 02940-3078

Notice to shareholders Source of distribution

Distribution period

March-2026

Distribution amount per share

$0.01454

The following table sets forth the estimated amounts of the current distribution and the cumulative distributions paid this fiscal year to date from the following sources: net investment income, net realized short-term capital gains, net realized long-term capital gains and return of capital or other capital source. The fund’s fiscal year begins each December 1st. All amounts are expressed per common share.

 

 

% Breakdown

Total cumulative

% Breakdown of the total

 

Current

of current

distributions for the

cumulative distributions

 

distribution

distribution

fiscal year to date

for the fiscal year to date

Net Investment Income

0.01091

75%

0.04079

70%

Net Realized ST Cap Gains

0.00000

0%

0.00000

0%

Net Realized LT Cap Gains

0.00000

0%

0.00000

0%

Return of Capital or

 

 

 

 

Other Capital Source

0.00363

25%

0.01748

30%

Total (per common share)

0.01454

100%

0.05827

100%

Average annual total return (in relation to NAV) for the five years ended 2-28-2026

3.95%

Annualized current distribution rate expressed as a percentage of month end NAV as of 2-28-2026

9.53%

Cumulative total return (in relation to NAV) for the fiscal year through 2-28-2026

2.02%

Cumulative fiscal year distributions as a percentage of NAV as of 2-28-2026

3.18%

You should not draw any conclusions about the fund's investment performance from the amount of this distribution or from the terms of the fund's managed distribution plan.

The fund estimates that it has distributed more than its income and capital gains; therefore, a portion of your distribution may be a return of capital. A return of capital may occur, for example, when some or all of the money that you invested in the fund is paid back to you. A return of capital distribution does not necessarily reflect the fund's investment performance and should not be confused with "yield" or "income."

The amounts and sources of distributions reported in this notice are only estimates and are not being provided for tax-reporting purposes. The actual amounts and sources of the amounts for tax-reporting purposes will depend upon the fund's investment experience during the remainder of its fiscal year and may be subject to changes based on tax regulations. The fund will send you a Form 1099-DIV for the calendar year that will tell you how to report these distributions for federal income tax purposes. If you have any questions regarding this information, please call our fund service department at 1-800-637-2304 any business day from 9 a.m. to 5 p.m. Eastern time.

CIHSN-0326

MFS® Intermediate High Income Fund

P.O. Box 43078

Providence, RI 02940-3078

Notice to shareholders Source of distribution

Distribution period

February-2026

Distribution amount per share

$0.01462

The following table sets forth the estimated amounts of the current distribution and the cumulative distributions paid this fiscal year to date from the following sources: net investment income, net realized short-term capital gains, net realized long-term capital gains and return of capital or other capital source. The fund’s fiscal year begins each December 1st. All amounts are expressed per common share.

 

 

% Breakdown

Total cumulative

% Breakdown of the total

 

Current

of current

distributions for the

cumulative distributions

 

distribution

distribution

fiscal year to date

for the fiscal year to date

Net Investment Income

0.00541

37%

0.02974

68%

Net Realized ST Cap Gains

0.00000

0%

0.00000

0%

Net Realized LT Cap Gains

0.00000

0%

0.00000

0%

Return of Capital or

 

 

 

 

Other Capital Source

0.00921

63%

0.01399

32%

Total (per common share)

0.01462

100%

0.04373

100%

Average annual total return (in relation to NAV) for the five years ended 1-31-2026

3.88%

Annualized current distribution rate expressed as a percentage of month end NAV as of 1-31-2026

9.53%

Cumulative total return (in relation to NAV) for the fiscal year through 1-31-2026

1.71%

Cumulative fiscal year distributions as a percentage of NAV as of 1-31-2026

2.38%

You should not draw any conclusions about the fund's investment performance from the amount of this distribution or from the terms of the fund's managed distribution plan.

The fund estimates that it has distributed more than its income and capital gains; therefore, a portion of your distribution may be a return of capital. A return of capital may occur, for example, when some or all of the money that you invested in the fund is paid back to you. A return of capital distribution does not necessarily reflect the fund's investment performance and should not be confused with "yield" or "income."

The amounts and sources of distributions reported in this notice are only estimates and are not being provided for tax-reporting purposes. The actual amounts and sources of the amounts for tax-reporting purposes will depend upon the fund's investment experience during the remainder of its fiscal year and may be subject to changes based on tax regulations. The fund will send you a Form 1099-DIV for the calendar year that will tell you how to report these distributions for federal income tax purposes. If you have any questions regarding this information, please call our fund service department at 1-800-637-2304 any business day from 9 a.m. to 5 p.m. Eastern time.

CIHSN-0226

MFS® Intermediate High Income Fund

P.O. Box 43078

Providence, RI 02940-3078

Notice to shareholders Source of distribution

Distribution period

January-2026

Distribution amount per share

$0.01457

The following table sets forth the estimated amounts of the current distribution and the cumulative distributions paid this fiscal year to date from the following sources: net investment income, net realized short-term capital gains, net realized long-term capital gains and return of capital or other capital source. The fund’s fiscal year begins each December 1st. All amounts are expressed per common share.

 

 

% Breakdown

Total cumulative

% Breakdown of the total

 

Current

of current

distributions for the

cumulative distributions

 

distribution

distribution

fiscal year to date

for the fiscal year to date

Net Investment Income

0.01457

100%

0.02911

100%

Net Realized ST Cap Gains

0.00000

0%

0.00000

0%

Net Realized LT Cap Gains

0.00000

0%

0.00000

0%

Return of Capital or

 

 

 

 

Other Capital Source

0.00000

0%

0.00000

0%

Total (per common share)

0.01457

100%

0.02911

100%

Average annual total return (in relation to NAV) for the five years ended 12-31-2025

3.71%

Annualized current distribution rate expressed as a percentage of month end NAV as of 12-31-2025

9.50%

Cumulative total return (in relation to NAV) for the fiscal year through 12-31-2025

0.85%

Cumulative fiscal year distributions as a percentage of NAV as of 12-31-2025

1.58%

You should not draw any conclusions about the fund's investment performance from the amount of this distribution or from the terms of the fund's managed distribution plan.

The fund estimates that it has distributed more than its income and capital gains; therefore, a portion of your distribution may be a return of capital. A return of capital may occur, for example, when some or all of the money that you invested in the fund is paid back to you. A return of capital distribution does not necessarily reflect the fund's investment performance and should not be confused with "yield" or "income."

The amounts and sources of distributions reported in this notice are only estimates and are not being provided for tax-reporting purposes. The actual amounts and sources of the amounts for tax-reporting purposes will depend upon the fund's investment experience during the remainder of its fiscal year and may be subject to changes based on tax regulations. The fund will send you a Form 1099-DIV for the calendar year that will tell you how to report these distributions for federal income tax purposes. If you have any questions regarding this information, please call our fund service department at 1-800-637-2304 any business day from 9 a.m. to 5 p.m. Eastern time.

CIHSN-0126

MFS® Intermediate High Income Fund

P.O. Box 43078

Providence, RI 02940-3078

Notice to shareholders Source of distribution

Distribution period

December-2025

Distribution amount per share

$0.01454

The following table sets forth the estimated amounts of the current distribution and the cumulative distributions paid this fiscal year to date from the following sources: net investment income, net realized short-term capital gains, net realized long-term capital gains and return of capital or other capital source. The fund’s fiscal year begins each December 1st. All amounts are expressed per common share.

 

 

% Breakdown

Total cumulative

% Breakdown of the total

 

Current

of current

distributions for the

cumulative distributions

 

distribution

distribution

fiscal year to date

for the fiscal year to date

Net Investment Income

0.01454

100%

0.01454

100%

Net Realized ST Cap Gains

0.00000

0%

0.00000

0%

Net Realized LT Cap Gains

0.00000

0%

0.00000

0%

Return of Capital or

 

 

 

 

Other Capital Source

0.00000

0%

0.00000

0%

Total (per common share)

0.01454

100%

0.01454

100%

Average annual total return (in relation to NAV) for the five years ended 11-30-2025

3.86%

Annualized current distribution rate expressed as a percentage of month end NAV as of 11-30-2025

9.48%

Cumulative total return (in relation to NAV) for the fiscal year through 11-30-2025

8.75%

Cumulative fiscal year distributions as a percentage of NAV as of 11-30-2025

0.79%

You should not draw any conclusions about the fund's investment performance from the amount of this distribution or from the terms of the fund's managed distribution plan.

The fund estimates that it has distributed more than its income and capital gains; therefore, a portion of your distribution may be a return of capital. A return of capital may occur, for example, when some or all of the money that you invested in the fund is paid back to you. A return of capital distribution does not necessarily reflect the fund's investment performance and should not be confused with "yield" or "income."

The amounts and sources of distributions reported in this notice are only estimates and are not being provided for tax-reporting purposes. The actual amounts and sources of the amounts for tax-reporting purposes will depend upon the fund's investment experience during the remainder of its fiscal year and may be subject to changes based on tax regulations. The fund will send you a Form 1099-DIV for the calendar year that will tell you how to report these distributions for federal income tax purposes. If you have any questions regarding this information, please call our fund service department at 1-800-637-2304 any business day from 9 a.m. to 5 p.m. Eastern time.

CIHSN-1225