# EDGAR Filing Document

**Accession Number:** 0001082744
**File Stem:** 0001082744-25-000110
**Filing Date:** 2025-12
**Character Count:** 34682
**Document Hash:** 58619083bb0144265ae385ee391a7338
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001082744-25-000110.hdr.sgml**: 20251203

**ACCESSION NUMBER**: 0001082744-25-000110

**CONFORMED SUBMISSION TYPE**: 497K

**PUBLIC DOCUMENT COUNT**: 3

**FILED AS OF DATE**: 20251203

**DATE AS OF CHANGE**: 20251203

**EFFECTIVENESS DATE**: 20251203

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Viking Mutual Funds
- **CENTRAL INDEX KEY:** 0001082744

**ORGANIZATION NAME:**
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 0731

**FILING VALUES:**
- **FORM TYPE:** 497K
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-77993
- **FILM NUMBER:** 251545230

**BUSINESS ADDRESS:**
- **STREET 1:** PO BOX 500
- **CITY:** MINOT
- **STATE:** ND
- **ZIP:** 58702-0500
- **BUSINESS PHONE:** 701-852-5292

**MAIL ADDRESS:**
- **STREET 1:** PO BOX 500
- **CITY:** MINOT
- **STATE:** ND
- **ZIP:** 58702-0500

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** VIKING MUTUAL FUNDS
- **DATE OF NAME CHANGE:** 19990325

## Series and Classes Contracts Data

### Maine Municipal Fund (Series ID: S000058943)

| Class ID   | Class Name   | Ticker Symbol   |
|:---|:---|:---|
| C000193244 | Class A      | MEMUX           |
| C000193245 | Class I      | MEIMX           |

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| | |
|:---|:---|
| **Maine Municipal Fund** | &nbsp;&nbsp; ![](x25120215103600.jpg) |
| &nbsp;&nbsp; Summary Prospectus ║ December 3, 2025 | &nbsp;&nbsp; ![](x25120215103600.jpg) |
| &nbsp;&nbsp; **Ticker:** MEMUX (Class A); MEIMX (Class I) | &nbsp;&nbsp; ![](x25120215103600.jpg) |

---

Before you invest, you may want to review the Fund's statutory prospectus and statement of additional information, which contain more information about the Fund and its risks. The current statutory prospectus and statement of additional information dated November 30, 2025 are incorporated by reference into this Summary Prospectus. You can find the Fund's statutory prospectus, statement of additional information, reports to shareholders, and other information about the Fund online at www.integrityvikingfunds/documents. You can also get this information at no cost by calling 800-276-1262 or by sending an email request to marketing@integrity.viking.com or from your financial professional.

**Investment Objective**

The Maine Municipal Fund (the "Fund") seeks the highest level of current income that is exempt from federal and Maine personal income taxes and is consistent with preservation of capital.

**Fees and Expenses of the Fund**

This table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund. **You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.** You may qualify for sales charge discounts with respect to purchases of Class A shares of the Fund if you and your family invest, or agree to invest in the future, at least $50,000 in the Fund or in other funds in the Integrity/Viking family of funds. More information about these and other discounts is available from your financial professional and in "The Shares Offered; Class A Shares" and "How to Buy Shares; Investor Services" on pages 44 and 49, respectively, of the Fund's prospectus, Appendix A of the Fund's prospectus, and "Buying and Selling Shares" on page B-27 of the Fund's statement of additional information.

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| | | |
|:---|:---|:---|
| &nbsp;&nbsp; **Shareholder Fees** (fees paid directly from your investment) | &nbsp;&nbsp; Class A<br> Shares | &nbsp;&nbsp; Class I<br> Shares |
| &nbsp;&nbsp; Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) | &nbsp;&nbsp; 2.50% |  |
| &nbsp;&nbsp; Maximum Deferred Sales Charge (Load) (as a percentage of the lesser of purchase price or redemption proceeds) | &nbsp;&nbsp; 1.00% |  |
| &nbsp;&nbsp; Maximum Sales Charge (Load) Imposed on Reinvested Dividends |  |  |
| &nbsp;&nbsp; Redemption Fee Imposed (as a percentage of amount redeemed, if applicable) |  |  |
| &nbsp;&nbsp; Exchange Fee |  |  |
| &nbsp;&nbsp; **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | &nbsp;&nbsp; **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | &nbsp;&nbsp; **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) |
| &nbsp;&nbsp; Management Fees | &nbsp;&nbsp; 0.50% | &nbsp;&nbsp; 0.50% |
| &nbsp;&nbsp; Distribution and Service (12b-1) Fees | &nbsp;&nbsp; 0.25% |  |
| &nbsp;&nbsp; Other Expenses | &nbsp;&nbsp; <u>1.08%</u> | &nbsp;&nbsp; <u>1.10%</u> |
| &nbsp;&nbsp; Total Annual Fund Operating Expenses | &nbsp;&nbsp; 1.83% | &nbsp;&nbsp; 1.60% |
| &nbsp;&nbsp; Fee Waivers and Expense Reimbursements<sup>(1)</sup> | &nbsp;&nbsp; <u>(0.85%)</u> | &nbsp;&nbsp; <u>(0.87%)</u> |
| &nbsp;&nbsp; Total Annual Fund Operating Expenses After Fee Waivers and Expense Reimbursements<sup>(1)</sup> | &nbsp;&nbsp; 0.98% | &nbsp;&nbsp; 0.73% |

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 <sup>(1)</sup> The Fund's investment adviser, Viking Fund Management, LLC (the "Adviser"), has contractually agreed to waive fees and reimburse expenses through November 29, 2026 so that Total Annual Fund Operating Expenses After Fee Waivers and Expense Reimbursements (excluding taxes, brokerage fees, commissions, extraordinary and non-recurring expenses, and acquired fund fees and expenses) do not exceed 0.98% for Class A Shares and 0.73% for Class I Shares of average daily net assets. This expense limitation agreement may only be terminated or modified prior to November 29, 2026 with the approval of the Fund's Board of Trustees. The terms of the expense limitation agreement provide that the Adviser is entitled to recoup such amounts waived or reimbursed for a period of up to three years from the date on which the Adviser waived fees or reimbursed expenses for the Fund. The Fund will make repayments to the Adviser only if such repayment does not cause the annual Fund operating expenses (after the repayment is taken into account) to exceed both (1) the expense limitation in place when such amounts were waived and (2) the Fund's current expense limitation.

**Example—**This Example is intended to help you compare the cost of investing in the Fund with the costs of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, that the Fund's operating expenses remain the same, and that the contractual expense limitation agreement remains in place for the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

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| | | | | |
|:---|:---|:---|:---|:---|
|  | &nbsp;&nbsp; **1 Year** | &nbsp;&nbsp; **3 Years** | &nbsp;&nbsp; **5 Years** | &nbsp;&nbsp; **10 Years** |
| &nbsp;&nbsp; **Redemption** |  |  |  |  |
| &nbsp;&nbsp;&nbsp; Class A | &nbsp;&nbsp; $347 | &nbsp;&nbsp; $731 | &nbsp;&nbsp; $1138 | &nbsp;&nbsp; $2776 |
| &nbsp;&nbsp;&nbsp; Class I | &nbsp;&nbsp; $75 | &nbsp;&nbsp; $420 | &nbsp;&nbsp; $789 | &nbsp;&nbsp; $1827 |

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**Portfolio Turnover—**The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the Example, affect the Fund's performance. During the most recent fiscal period, the Fund's portfolio turnover rate was 18.05% of the average value of its portfolio.

Summary Prospectus \| Maine Municipal Fund \| December 3, 2025<br> Page 1

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**Principal Investment Strategies**

To pursue its objective, the Fund normally invests at least 80% of its net assets (including any borrowings for investment purposes) in municipal securities that pay interest free from (a) federal income taxes, including the federal alternative minimum tax, and (b) Maine personal income taxes.

Municipal bonds are debt securities issued by or on behalf of states, territories, and possessions of the United States and their political subdivisions, agencies, authorities, and instrumentalities. The two general classifications of municipal bonds are "general obligation" and "revenue" bonds. General obligation bonds are secured by the issuer's pledge of its faith, credit, and taxing power for the payment of principal and interest. Revenue bonds are payable only from the revenues derived from a particular facility or class of facilities or, in some cases, from the proceeds of a special excise tax or other specific revenue source.

The investment manager actively manages the Fund's portfolio by selecting securities that it believes will provide the best balance between risk and return within the Fund's range of allowable investments. The investment manager will consider selling a security with deteriorating credit or limited upside potential compared to other available bonds.

The Fund may invest up to 30% of its net assets in U.S. territorial obligations (including qualifying obligations of Puerto Rico, the U.S. Virgin Islands, and Guam), the interest on which is exempt from federal and Maine personal income taxes. The Fund may invest up to 20% of its net assets in private activity bonds (which are revenue bonds that finance privately operated facilities), the interest on which is a tax preference item for purposes of the federal alternative minimum tax.

The Fund may invest more than 25% of its net assets in municipal securities that finance similar types of projects, such as education, healthcare, housing, industrial development, transportation, utilities, or pollution control. Economic, business, political, or other changes can affect all securities of a similar type.

All of the municipal securities in which the Fund invests are rated investment grade (BBB- or higher) at the time of purchase by a nationally recognized statistical rating service such as S&P Global Ratings or Moody's Investors Service, Inc. or are of comparable quality as determined by the Fund's investment manager. If, subsequent to the purchase of a municipal security, the rating of a municipal security falls below investment grade, the Fund will not be required to dispose of the security.

Under normal circumstances, the Fund will maintain an average stated maturity at between five and twenty-five years.

The Fund is non-diversified and therefore may invest a greater percentage of its assets in securities of a more limited number of issuers compared to a diversified mutual fund.

**Principal Risks**

***As with all mutual funds, there is the risk that you could lose money through your investment in the Fund. Many factors affect the Fund's net asset value and performance. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.***

***General market risk.*** There is no assurance that the Fund will meet its investment objective. The prices of the securities in which the Fund invests may fluctuate as a result of market factors such as interest rates, credit spreads, or commodity prices, and the Fund's share price and the value of your investment may change. Since the value of the Fund's shares can go up or down, it is possible to lose money by investing in the Fund.

***Non-diversified fund risk.*** Because a relatively high percentage of the Fund's assets may be invested in the securities of a limited number of issuers, the Fund's portfolio may be more susceptible to any single event impacting the market value and returns of any one issuer than a diversified fund.

***Municipal securities risk.*** The values of municipal securities may be adversely affected by a number of factors, including adverse tax, legislative, political, or interest rate changes, general economic and market conditions, and the financial condition of the issuers of municipal securities.

***Single state risks.*** Because the Fund invests primarily in the municipal securities of Maine, it is particularly susceptible to any economic, political, or regulatory developments affecting a particular issuer or issuers of the Maine municipal securities in which it invests. Investing primarily in issues of a single state makes the Fund more sensitive to risks specific to the state. To the extent it invests a significant portion of its assets in the municipal securities of U.S. territories and possessions, the Fund will also be more sensitive to risks specific to such U.S. territories and possessions.

Summary Prospectus \| Maine Municipal Fund \| December 3, 2025<br> Page 2

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***Interest rate risk.*** Interest rate risk is the risk that debt securities will decline in value because of changes in interest rates. As nominal interest rates rise, the value of certain debt securities held by the Fund is likely to decrease. Debt securities with longer maturities tend to be more sensitive to changes in interest rates, usually making them more volatile than securities with shorter maturities.

***Income risk.*** The income from the Fund's portfolio may decline because of falling market interest rates. This can result when the Fund invests the proceeds from new share sales, or from matured or called bonds, at market rates that are below the portfolio's current earnings rate.

***Liquidity risk.*** Liquidity risk is the risk that the Fund may not be able to sell a holding in a timely manner at a desired price. Liquidity risk may result from the lack of an active market, the reduced number of traditional market participants, or the reduced capacity of traditional market participants to make a market in securities. The secondary market for certain municipal securities tends to be less developed and liquid than many other securities markets, which may adversely affect the Fund's ability to sell such municipal securities at attractive prices.

***Maturity risk.*** Generally, longer-term securities are more susceptible to changes in value as a result of interest rate changes than are shorter-term securities.

***Credit risk.*** Credit risk is the possibility that an issuer will be unable to make interest payments or repay principal. Changes in an issuer's financial strength or in a security's credit rating may affect its value. Securities supported by insurance or other credit enhancements also have the credit risk of the entity providing the insurance or other credit support. Changes in the credit quality of the insurer or other credit provider could affect the value of the security and the Fund's share price. Not all securities are rated. In the event that rating agencies assign different ratings to the same security, the Fund's investment manager will determine which rating it believes best reflects the security's quality and risk at that time. Credit risks associated with certain particular classifications of municipal securities include:

***General Obligation Bonds***-Timely payments depend on the issuer's credit quality, ability to raise tax revenues, and ability to maintain an adequate tax base.

***Revenue Bonds***-Payments depend on the money earned by the particular facility or class of facilities, or the amount of revenues derived from another source.

***Private Activity Bonds***-Municipalities and other public authorities issue private activity bonds to finance development of facilities for use by a private enterprise. The private enterprise pays the principal and interest on the bond, and the issuer does not pledge its full faith, credit, and taxing power for repayment.

***Municipal insurance risk.*** The Fund's investments may include investments in insured municipal securities. Municipal security insurance does not guarantee the value of either individual municipal securities or of shares of the Fund. In addition, a municipal security insurance policy generally will not cover: (i) repayment of a municipal security before maturity (redemption), (ii) prepayment or payment of an acceleration premium (except for a mandatory sinking fund redemption) or any other provision of a bond indenture that advances the maturity of the bond or (iii) nonpayment of principal or interest caused by negligence or bankruptcy of the paying agent. A mandatory sinking fund redemption may be a provision of a municipal security issue whereby part of the municipal security issue may be retired before maturity. Downgrades and withdrawal of ratings from insurers of municipal securities have substantially limited the availability of insurance sought by issuers of municipal securities thereby reducing the supply of insured municipal securities. Because of the consolidation among insurers of municipal securities, to the extent that the Fund invests in insured municipal securities, it is subject to the risk that credit risk may be concentrated among fewer insurers and the risk that events involving one or more insurers could have a significant adverse effect on the value of the securities insured by an insurer and on the municipal markets as a whole.

***Call risk.*** Call risk is the likelihood that a security will be prepaid (or "called") before maturity. An issuer is more likely to call its bonds when interest rates are falling, because the issuer can issue new bonds with lower interest payments. If a bond is called, the Fund may have to replace it with a lower-yielding security.

***Extension risk.*** Extension risk is the risk that an issuer will exercise its right to pay principal on an obligation held by the Fund later than expected. This may happen during a period of rising interest rates. Under these circumstances, the value of the obligation will decrease and the Fund will suffer from the inability to invest in higher yielding securities.

***Portfolio strategy risk.*** The investment manager's skill in choosing appropriate investments for the Fund will determine in part the Fund's ability to achieve its investment objective.

***Inflation risk.*** There is a possibility that the rising prices of goods and services may have the effect of offsetting a Fund's real return. This is likely to have a greater impact on the returns of bond funds and money market funds, which historically have had more modest returns in comparison to equity funds. As inflation increases, the value of the Fund's assets can decline as can the value of the Fund's distributions.

***Tax risk.*** Income from municipal securities held by the Fund could be declared taxable because of unfavorable changes in tax laws, adverse interpretations by the Internal Revenue Service or state tax authorities, or noncompliant conduct of a bond issuer. Moreover, a portion of the Fund's otherwise exempt-interest dividends may be taxable to those shareholders subject to the federal alternative minimum tax. In addition, proposals have been made to restrict or eliminate the federal income tax exemption for interest on municipal securities, and similar proposals may be introduced in the future. Proposed "flat tax" and "value added tax" proposals could also have the effect of eliminating the tax preference for municipal securities. Some of these proposals would apply to interest on municipal securities issued before the date of enactment, which would adversely affect their value to a material degree. If such a proposal were enacted, the availability of municipal securities for investment by the Fund and the value of the Fund's portfolio would be adversely affected.

Summary Prospectus \| Maine Municipal Fund \| December 3, 2025<br> Page 3

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***Municipal sector risk.*** The Fund may invest more than 25% of its total assets in municipal securities that finance, or pay interest from the revenues of, similar projects that tend to be impacted the same or similar ways by economic, business, or political developments, which would increase credit risk. For example, legislation on the financing of a project or a declining economic need for the project would likely affect all similar projects.

***Risks of health care revenue bonds.*** The Fund may invest in health care revenue bonds. The health care sector is subject to regulatory action by a number of private and governmental agencies, including federal, state, and local governmental agencies. A major source of revenues for the health care sector is payments from the Medicare and Medicaid programs. As a result, the sector is sensitive to legislative changes and reductions in governmental spending for such programs. Numerous other factors may affect the sector, such as general economic conditions; demand for services; expenses (including malpractice insurance premiums); and competition among health care providers. In addition, various factors may adversely affect health care facility operations, including adoption of national, state and/or local health care reform measures; medical and technological advances which dramatically alter the need for health services or the way in which such services are delivered; changes in medical coverage which alter the traditional fee-for-service revenue stream; and efforts by employers, insurers and governmental agencies to reduce the costs of health care insurance and health care services.

***Risks of housing revenue bonds.*** The Fund may invest in housing revenue bonds. Housing revenue bonds are generally issued by a state, county, city, local housing authority, or other public agency. They generally are secured by the revenues derived from mortgages purchased with the proceeds of the bond issue. It is extremely difficult to predict the supply of available mortgages to be purchased with the proceeds of an issue or the future cash flow from the underlying mortgages. Consequently, there are risks that proceeds will exceed supply, resulting in early retirement of bonds, or that homeowner repayments will create an irregular cash flow. Many factors may affect the financing of multi-family housing projects, including acceptable completion of construction, proper management, occupancy and rent levels, economic conditions, and changes to current laws and regulations.

***Risks of transportation revenue bonds.*** The Fund may invest in transportation revenue bonds. Transportation debt may be issued to finance the construction of airports, toll roads, highways, or other transit facilities. Airport bonds are dependent on the general stability of the airline industry and on the stability of a specific carrier who uses the airport as a hub. Air traffic generally follows broader economic trends and is also affected by the price and availability of fuel. Toll road bonds are also affected by the cost and availability of fuel as well as toll levels, the presence of competing roads and the general economic health of an area. Fuel costs and availability also affect other transportation-related securities, as does the presence of alternate forms of transportation, such as public transportation.

***Risks of educational revenue bonds.*** The Fund may invest in educational revenue bonds. These include municipal securities that are obligations of issuers which are, or which govern the operation of, schools, colleges, and universities and whose revenues are derived mainly from ad valorem taxes, or for higher education systems, from tuition, dormitory revenues, grants, and endowments. Litigation or legislation pertaining to ad valorem taxes may affect sources of funds available for the payment of school bonds. College and university obligations may be affected by the possible inability to raise tuitions and fees sufficiently to cover increased operating costs, the uncertainty of continued receipt of federal grants and state funding, and new government or legislation or regulations which may adversely affect the revenues or costs of such issuers. In addition, student loan revenue bonds, which are generally offered by state (or sub-state) authorities or commissions and backed by pools of student loans, may be affected by numerous factors, including the rate of student loan defaults, seasoning of the loan portfolio, student repayment deferral periods of forbearance, potential changes in federal legislation, and state guarantee agency reimbursement.

***Risks of electric utility revenue bonds.*** The Fund may invest in electric utility revenue bonds. Risks associated with electric utility revenue bonds include: (a) the availability and costs of fuel; (b) the availability and costs of capital; (c) the effects of conservation on energy demand; (d) the effects of rapidly changing environmental, safety, and licensing requirements, and other federal, state and local regulations; and (e) timely and sufficient rate increases.

***Risks of gas utility revenue bonds.*** The Fund may invest in gas utility revenue bonds. Gas utilities are subject to the risks of supply conditions and increased competition from other providers of utility services. In addition, gas utilities are affected by gas prices, which may be magnified to the extent that a gas company enters into long-term contracts for the purchase or sale of gas at fixed prices, since such prices may change significantly and to the disadvantage of the gas utility in the open market. Gas utilities are particularly susceptible to supply and demand imbalances due to unpredictable climate conditions and other factors and are subject to regulatory risks as well.

***Risks of water and sewer revenue bonds.*** The Fund may invest in water and sewer revenue bonds. Issuers of water and sewer bonds face public resistance to rate increases, costly environmental litigation and federal environmental mandates. In addition, the lack of water supply due to insufficient rain, run-off, or snow pack may be a concern.

Summary Prospectus \| Maine Municipal Fund \| December 3, 2025<br> Page 4

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***Cybersecurity risk.*** Cybersecurity breaches may allow an unauthorized party to gain access to Fund assets, customer data, or proprietary information, or cause the Fund and/or its service providers to suffer data corruption or lose operational functionality. The Fund's share price may decline as a result of unauthorized actions taken during a security breach or subsequent market activity in response to the security breach.

***Valuation risk.*** The sales price the Fund could receive for any particular portfolio investment may differ from the Fund's valuation of the investment, particularly for securities that trade in thin or volatile markets or that are valued using a fair value methodology.

**Fund Performance**

The following bar chart and table provide some indication of the risks of investing in the Fund. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available at <u>www.integrityvikingfunds.com</u> or by calling 800-276-1262.

The bar chart below shows the variability of the Fund's performance from year to year for Class A shares. The bar chart and highest/lowest quarterly returns that follow do not reflect sales charges, and if these charges were reflected, the returns would be less than those shown.

![](x25120215103600.gif)

During the ten-year period shown in the bar chart, the highest return for a quarter was 7.29% (quarter ended December 31, 2023) and the lowest return for a quarter was -5.55% (quarter ended March 31, 2022). The Fund's calendar year-to-date total return as of September 30, 2025 was 1.24%.

The table below presents the Fund's average annual total returns for Class A shares over 1-, 5-, and 10-year periods, and for Class I shares over 1- and 5-year periods and since inception, compared with a broad measure of market performance. The return information below reflects applicable sales charges. After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. After-tax returns are shown for Class A shares of the Fund only; after-tax returns for Class I shares will vary. Actual after-tax returns depend on an investor's tax situation and may differ from those shown, and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts ("IRAs").

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| | | | | | |
|:---|:---|:---|:---|:---|:---|
| &nbsp;&nbsp; **Average Annual Total Returns**<br> (for the periods ended December 31, 2024) | &nbsp;&nbsp; **Average Annual Total Returns**<br> (for the periods ended December 31, 2024) | &nbsp;&nbsp; **Average Annual Total Returns**<br> (for the periods ended December 31, 2024) | &nbsp;&nbsp; **Average Annual Total Returns**<br> (for the periods ended December 31, 2024) | &nbsp;&nbsp; **Average Annual Total Returns**<br> (for the periods ended December 31, 2024) | &nbsp;&nbsp; **Average Annual Total Returns**<br> (for the periods ended December 31, 2024) |
|  |  | &nbsp;&nbsp; **<u>1 Year</u>** | &nbsp;&nbsp; **<u>5 Years</u>** | &nbsp;&nbsp; **<u>10 Years</u>** | &nbsp;&nbsp; **<u>Since Inception</u>** |
| &nbsp;&nbsp; **Class A** *(Inception date: December 5, 1991)* | &nbsp;&nbsp; **Class A** *(Inception date: December 5, 1991)* |  |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp; Return Before Taxes | &nbsp;&nbsp;&nbsp;&nbsp; Return Before Taxes | &nbsp;&nbsp; -2.60% | &nbsp;&nbsp; -1.14% | &nbsp;&nbsp; 0.36% | &nbsp;&nbsp; — |
| &nbsp;&nbsp;&nbsp;&nbsp; Return After Taxes on Distributions | &nbsp;&nbsp;&nbsp;&nbsp; Return After Taxes on Distributions | &nbsp;&nbsp; -2.57% | &nbsp;&nbsp; -1.14% | &nbsp;&nbsp; 0.36% | &nbsp;&nbsp; — |
| &nbsp;&nbsp;&nbsp;&nbsp; Return After Taxes on Distributions and Sale of Fund Shares | &nbsp;&nbsp;&nbsp;&nbsp; Return After Taxes on Distributions and Sale of Fund Shares | &nbsp;&nbsp; -1.31% | &nbsp;&nbsp; -0.37% | &nbsp;&nbsp; 0.79% | &nbsp;&nbsp; — |
| &nbsp;&nbsp; **Class I** *(Inception date: November 1, 2017)* | &nbsp;&nbsp; **Class I** *(Inception date: November 1, 2017)* |  |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp; Return Before Taxes | &nbsp;&nbsp;&nbsp;&nbsp; Return Before Taxes | &nbsp;&nbsp; 0.15% | &nbsp;&nbsp; -0.37% | &nbsp;&nbsp; — | &nbsp;&nbsp; 0.50% |
| &nbsp;&nbsp; **Bloomberg U.S. Municipal Bond Index**<sup>(1)</sup> (reflects no deduction for fees, expenses, or taxes) | &nbsp;&nbsp; **Bloomberg U.S. Municipal Bond Index**<sup>(1)</sup> (reflects no deduction for fees, expenses, or taxes) | &nbsp;&nbsp; 1.05% | &nbsp;&nbsp; 0.99% | &nbsp;&nbsp; 2.25% | &nbsp;&nbsp; 1.97% (Class I) |
| &nbsp;&nbsp; <sup>(1)</sup> | &nbsp;&nbsp; The Bloomberg U.S. Municipal Bond Index is an unmanaged index that includes investment-grade, tax-exempt, and fixed-rate bonds with maturities greater than two years selected from issues larger than $75 million. | &nbsp;&nbsp; The Bloomberg U.S. Municipal Bond Index is an unmanaged index that includes investment-grade, tax-exempt, and fixed-rate bonds with maturities greater than two years selected from issues larger than $75 million. | &nbsp;&nbsp; The Bloomberg U.S. Municipal Bond Index is an unmanaged index that includes investment-grade, tax-exempt, and fixed-rate bonds with maturities greater than two years selected from issues larger than $75 million. | &nbsp;&nbsp; The Bloomberg U.S. Municipal Bond Index is an unmanaged index that includes investment-grade, tax-exempt, and fixed-rate bonds with maturities greater than two years selected from issues larger than $75 million. | &nbsp;&nbsp; The Bloomberg U.S. Municipal Bond Index is an unmanaged index that includes investment-grade, tax-exempt, and fixed-rate bonds with maturities greater than two years selected from issues larger than $75 million. |

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**Management**

**Investment Adviser**—Viking Fund Management, LLC is the Fund's investment adviser.

**Portfolio Managers—**Shannon D. Radke, Senior Portfolio Manager and President of Viking Fund Management, LLC, has served as the Fund's portfolio manager since November 2010. Josh Larson, Portfolio Manager, has served as the Fund's portfolio manager since November 2014.

**Purchase and Sale of Fund Shares**

You may purchase, redeem, or exchange shares of the Fund on any business day, which is any day the New York Stock Exchange is open for business. You may purchase, redeem, or exchange shares of the Fund either through a financial advisor or directly from the Fund.

Summary Prospectus \| Maine Municipal Fund \| December 3, 2025<br> Page 5

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The minimum initial purchase or exchange into the Fund is $1,000 ($50 for accounts opened through an automatic investment plan account and $250 for an IRA account). The minimum subsequent investment is $50. The Fund may, however, accept investments of smaller initial or subsequent amounts at its discretion. Class I shares are not available for IRAs or employer sponsored IRAs, unless purchased through a fee-based advisory account with a financial intermediary. You may contact the Fund's transfer agent, Integrity Fund Services, LLC, by mail at PO Box 759, Minot, ND 58702, or by calling 800-601-5593.

**Tax Information**

Distributions of the Fund's net interest income from tax-exempt securities are generally expected to be exempt from regular federal income tax and Maine state income tax; however, distributions derived from interest paid on certain "private activity bonds" may be subject to the federal alternative minimum tax. In addition, a portion of the Fund's distributions may be taxable as ordinary income or capital gains and subject to state and local taxes including Maine state income tax. The tax treatment of distributions is the same whether you reinvest them in additional Fund shares or receive them in cash.

**Payments to Broker-Dealers and Other Financial Intermediaries**

If you purchase the Fund through a broker-dealer or other financial intermediary (such as a bank), the Fund and its related companies may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary's website for more information.

Summary Prospectus \| Maine Municipal Fund \| December 3, 2025<br> Page 6