Core Bond Fund

C000074783 Fund Overview

Core Bond Fund is a US mutual fund managed by Ultra Series Fund, categorised as Long Securitized (MBS/ABS/CMBS) Bond. ABC INVEST provides holdings, performance, costs, cashflows, risk data, prospectus documents and SEC filings, sourced from SEC filings.

• Type: US mutual fund
• Manager: Ultra Series Fund
• Category: Long Securitized (MBS/ABS/CMBS) Bond
• Assets under management: $45.91M
• 1-year return: 3.7%
• SEC CIK: 0000732697
• SEC series ID: S000019978
• Share class ID: C000074783

C000074783 Investment Objective and Strategy

Core Bond Fund describes its objective and strategy as follows, from its latest prospectus filed with the SEC by Ultra Series Fund.

Investment objective

The Core Bond Fund seeks to generate a high level of current income, consistent with the prudent limitation of investment risk.

Principal investment strategy

Under normal market conditions, the Fund invests at least 80% of its net assets (including borrowings for investment purposes) in bonds. To keep current income relatively stable and to limit share price volatility, the Fund emphasizes investment grade securities and maintains an intermediate (typically 3-7 year) average portfolio duration , with the goal of being between 85-115% of the market benchmark duration (for this purpose, the benchmark used is the Bloomberg U.S. Aggregate Bond Index, the duration of which as of December 31, 2025 was 5.81 years). Duration is an approximation of the expected change in a debt securitys price given a 1% move in interest rates, using the following formula: [change in debt security value = (change in interest rates) x (duration) x (-1)]. By way of example, assume XYZ company issues a five year bond which has a duration of 4.5 years.

If interest rates were to instantly increase by 1%, the bond would be expected to decrease in value by approximately 4.5%. The Fund is managed so that, under normal market conditions, the weighted average life of the Fund will be 10 years or less. The weighted average life of the Fund as of December 31, 2025 was 8.24 years. The Fund strives to add incremental return in the portfolio by making strategic decisions relating to credit risk, sector exposure and yield curve positioning. The Fund generally holds 100-500 individual securities in its portfolio at any given time and may invest in the following instruments: ? Corporate debt securities: securities issued by domestic and foreign corporations which have a rating within the four highest categories and, to a limited extent (up to 20% of its assets), in securities not rated within the four highest categories (i.e., junk bonds).

The Funds investment adviser, Madison Asset Management, LLC (Madison), will only invest in lower-grade securities when it believes that the creditworthiness of the issuer is stable or improving, and when the potential return of investing in such securities justifies the higher level of risk; ? U.S. Government debt securities: securities issued or guaranteed by the U.S. Government or its agencies or instrumentalities; ? Foreign government debt securities: securities issued or guaranteed by a foreign (including emerging market) government or its agencies or instrumentalities, payable in U.S. dollars, which have a rating within the four highest categories; ? Non-rated debt securities: securities issued or guaranteed by corporations, financial institutions, and others which, although not rated by a national rating service, are considered by Madison to have an investment quality equivalent to those categories in which the Fund is permitted to invest (including up to 20% of the Funds assets in junk bonds); and ?

Asset-backed, mortgage-backed and commercial mortgage-backed securities: securities issued or guaranteed by special purpose corporations and financial institutions that represent direct or indirect participation in, or are collateralized by, an underlying pool of assets. The types of assets that can be securitized include, among others, residential or commercial mortgages, credit card receivables, automobile loans, and other assets. Madison may alter the composition of the Fund with regard to quality and maturity and may sell securities prior to maturity. Under normal market conditions, however, turnover for the Fund is generally not expected to exceed 100%. Sales of Fund securities may result in capital gains. This can occur any time Madison sells a bond at a price that was higher than the purchase price, even if Madison does not engage in active or frequent trading.

Madisons intent when it sells bonds is to lock in any gains already achieved by that investment or, alternatively, prevent additional or potential losses that could occur if Madison continued to hold the bond. Turnover may also occur when Madison finds an investment that could generate a higher return than the investment currently held. However, increasing portfolio turnover at a time when Madisons assessment of market performance is incorrect could lower investment performance. The Fund pays implied brokerage commissions when it purchases or sells bonds, which is the difference between the bid and ask price. As a result, as portfolio turnover increases, the cumulative effect of this may hurt Fund performance. Under normal market conditions, the Fund will not engage in active or frequent trading of its bonds.

However, it is possible that Madison will determine that market conditions require a significant change to the composition of the Funds portfolio. For example, if interest rates begin to rise, Madison may attempt to sell bonds in anticipation of further rate increases before they lose more value. Also, if the Fund experiences large swings in shareholder purchases and redemptions, Madison may be required to sell bonds more frequently in order to generate the cash needed to pay redeeming shareholders. Madison reserves the right to invest a portion of the Funds assets in short-term debt securities (i.e., those with maturities of one year or less) and to maintain a portion of Fund assets in uninvested cash. However, Madison does not intend to hold more than 35% of the Funds assets in such investments, unless Madison determines that market conditions warrant a temporary defensive investment position.

Under such circumstances, the Fund may invest up to 100% in cash, money market funds, and/or tax-free money market instruments. To the extent the Fund engages in this temporary defensive position, the Funds ability to achieve its investment objective may be diminished. Short-term investments may include investment grade certificates of deposit, commercial paper and repurchase agreements. Madison might hold substantial cash reserves in seeking to reduce the Funds exposure to bond price depreciation during a period of rising interest rates and to maintain desired liquidity while awaiting more attractive investment conditions in the bond market. The Funds investment strategy reflects Madisons general Participate and Protect investment philosophy. Madisons expectation is that investors in the Fund will participate in market appreciation during bull markets and experience something less than full participation during bear markets compared with investors in portfolios holding more speculative and volatile securities; therefore, this investment philosophy is intended to represent a conservative investment strategy.

There is no assurance that Madisons expectations regarding this investment strategy will be realized.

C000074783 Holdings

Top 10 holdings of Core Bond Fund by percentage of net assets, from the fund's latest SEC N-PORT filing.

View all C000074783 holdings

C000074783 Portfolio Allocation

Asset-class allocation of Core Bond Fund by percentage of net assets, from the latest SEC N-PORT filing.

C000074783 Performance

Total returns for C000074783 (as of 2026-10-01), from SEC filings.

C000074783 Risk Information

Risk metrics for C000074783, derived from monthly returns in SEC filings.

• 1-year volatility (annualised): 3.1%

C000074783 Costs and Fees

C000074783 costs about $83 per $10,000 invested per year in fund expenses.

• Net expense ratio: 0.83%
• Gross expense ratio: 0.83%
• Portfolio turnover: 13%
• Brokerage commissions: 0.00 bps of average net assets (SEC N-CEN)

C000074783 Cashflows

Over the 12 months to 2026-06, Core Bond Fund had net outflows of $7.77M, from monthly SEC N-PORT filings.

C000074783 Debt Constituents

Largest debt holdings of Core Bond Fund by percentage of net assets, from the latest SEC N-PORT filing.

C000074783 Prospectus and SEC Filings

Official Core Bond Fund filings on SEC EDGAR — prospectus, portfolio holdings and annual reports.

• Prospectus (485BPOS) — filed 2026-04-29
• Prospectus (485BPOS) — filed 2025-04-30
• Prospectus (485BPOS) — filed 2024-04-25
• Portfolio holdings (N-PORT) — filed 2026-08-21
• Portfolio holdings (N-PORT) — filed 2026-05-22
• Portfolio holdings (N-PORT) — filed 2026-02-10
• Annual census (N-CEN) — filed 2026-03-10
• Annual census (N-CEN) — filed 2025-03-11

Related Funds

Other Long Securitized (MBS/ABS/CMBS) Bond funds tracked on ABC INVEST:

• PIMCO Income Fund (PONAX)
• Bridge Builder Core Plus Bond Fund (BBCPX)
• iShares MBS ETF (MBB)
• Guggenheim Total Return Bond Fund (GIBAX)
• Janus Henderson AAA CLO ETF (JAAA)

Data Sources

ABC INVEST compiles this page from public filings made to the U.S. Securities and Exchange Commission (SEC) through EDGAR: portfolio holdings and monthly cashflows from Form N-PORT, expenses and returns from fund prospectuses (Form 485BPOS) and the SEC DERA Risk/Return Summary data sets, annual data from Form N-CEN, and shareholder reports from Form N-CSR.