SUMMARY PROSPECTUS

ADJUSTABLE GOVERNMENT SECURITIES FUND

March 1, 2022

as amended October 26, 2022

Class A	Class A1	Class C	Class R6	Advisor Class
FISAX	FAUGX	FCSCX	FAURX	FAUZX

Before you invest, you may want to review the Fund’s prospectus, which contains more information about the Fund and its risks. You can find the Fund’s prospectus, statement of additional information, reports to shareholders and other information about the Fund online at www.franklintempleton.com/prospectus. You can also get this information at no cost by calling (800) DIAL BEN/342-5236 or by sending an e-mail request to prospectus@franklintempleton.com. The Fund’s prospectus and statement of additional information, both dated March 1, 2022, as may be supplemented, are all incorporated by reference into this Summary Prospectus.

Adjustable Government Securities Fund

The Board of Trustees of the Trust recently approved changes to the Fund’s name, investment goal, 80% investment policy, investment strategies and benchmark. The Fund will be named the Franklin Low Duration U.S. Government Securities Fund, and, under normal market conditions, the Fund will invest at least 80% of its net assets in U.S. government securities. The changes to the Fund’s 80% investment policy will allow the Fund to invest in a more diverse set of government securities, which would include, among others, adjustable and fixed-rate mortgage-backed securities, including collateralized mortgage obligations. In connection with the changes, the Fund’s primary benchmark will be changed to the Bloomberg US Government (1-3 Year) Index.

The changes are subject to shareholder approval of changes to the Fund’s investment goal. It is anticipated that in December 2022 shareholders of the Fund will receive a proxy statement requesting their votes on changes to the Fund’s investment goal and other matters. If the proposal to change the Fund’s investment goal is approved by the Fund’s shareholders, the changes are expected to be effective on or about March 1, 2023.

The Fund reserves the right to change the above at any time.

Investment Goal

High level of current income, while providing lower volatility of principal than a fund that invests in fixed-rate securities.

Fees and Expenses of the Fund

These tables describe the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may qualify for sales charge discounts in Class A if you and your family invest, or agree to invest in the future, at least $100,000 in Franklin Templeton funds. More information about these and other discounts is available from your financial professional and under “Your Account” on page 153 in the Fund's Prospectus and under “Buying and Selling Shares” on page 92 of the Fund’s Statement of Additional Information. In addition, more information about sales charge discounts and waivers for purchases of shares through specific financial intermediaries is set forth in Appendix A - "Intermediary Sales Charge Discounts and Waivers" to the Fund's prospectus.

Please note that the tables and examples below do not reflect any transaction fees that may be charged by financial intermediaries, or commissions that a shareholder may be required to pay directly to its financial intermediary when buying or selling Class R6 or Advisor Class shares.

Shareholder Fees

(fees paid directly from your investment)

		Class A		Class A1		Class C	Class R6	Advisor Class
Maximum Sales Charge (Load) Imposed on Purchases (as percentage of offering price)		2.25%		2.25%		None	None	None
Maximum Deferred Sales Charge (Load) (as percentage of the lower of original purchase price or sale proceeds)		None	1	None	1	1.00%	None	None
1.	There is a 1% contingent deferred sales charge that applies to investments of $500,000 or more (see "Investment of $500,000 or More" under "Choosing a Share Class") and purchases by certain retirement plans without an initial sales charge on shares sold within 18 months of purchase.

As of June 18, 2014, Class A1 shares are only available to existing Class A1 shareholders. Class A1 shares are not available to new investors. If you are a Class A1 shareholder, you may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in Franklin Templeton funds.

Annual Fund Operating Expenses

(expenses that you pay each year as a percentage of the value of your investment)

	Class A	Class A1	Class C	Class R6	Advisor Class
Management fees	0.50%	0.50%	0.50%	0.50%	0.50%
Distribution and service (12b-1) fees	0.25%	0.10%	0.65%	None	None
Other expenses1	0.22%	0.22%	0.22%	0.13%	0.22%
Total annual Fund operating expenses	0.97%	0.82%	1.37%	0.63%	0.72%
Fee waiver and/or expense reimbursement1,2	-0.12%	-0.12%	-0.12%	-0.14%	-0.12%
Total annual Fund operating expenses after fee waiver and/or expense reimbursement1,2	0.85%	0.70%	1.25%	0.49%	0.60%

^1. The transfer agent has contractually agreed to cap transfer agency fees for Class R6 shares for the Fund so that transfer agency fees for that class do not exceed 0.03% until February 28, 2023. During this term, this fee waiver and expense reimbursement agreement may not be terminated or amended without approval of the board of trustees except to add series and classes, to reflect the extension of termination dates or to lower the fee waiver and expense limitation.

^2. The investment manager has contractually agreed to waive or assume certain expenses so that operating expenses (excluding Rule 12b-1 fees, acquired fund fees and expenses and certain non-routine expenses) for each class of the Fund do not exceed 60% until February 28, 2023. During its term, this fee waiver and expense reimbursement agreement may not be terminated or amended without approval of the board of trustees except to add series and classes, to reflect the extension of termination dates or to lower the cap on Fund's fees and expenses (which would result in lower fees for shareholders).

Example

This Example is intended to help you compare the cost of investing in the Fund with the cost 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 the period. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. The Example reflects adjustments made to the Fund's operating expenses due to the fee waivers and/or expense reimbursements by management for the 1 Year numbers only. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

	1 Year	3 Years	5 Years	10 Years
Class A	$310	$516	$738	$1,378
Class A1	$295	$469	$659	$1,206
Class C	$227	$422	$738	$1,526
Class R6	$50	$187	$336	$772
Advisor Class	$61	$218	$388	$883
If you do not sell your shares:
Class C	$127	$422	$738	$1,526

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 year, the Fund's portfolio turnover rate was 68.61% of the average value of its portfolio.

Principal Investment Strategies

Under normal market conditions, the Fund invests at least 80% of its net assets in “adjustable-rate U.S. government mortgage securities.” “Adjustable-rate U.S. government mortgage securities” include adjustable-rate mortgage securities (ARMS) and other mortgage-backed securities, including collateralized mortgage obligations (CMOs), with interest rates that adjust periodically to reflect prevailing market interest rates, which are issued or guaranteed by the U.S. government, its agencies or instrumentalities, including government-sponsored entities.

Mortgage-backed securities represent an interest in a pool of mortgage loans made by banks and other financial institutions to finance purchases of homes, commercial buildings and other real estate. As the underlying mortgage loans are paid off, investors receive periodic principal and interest payments as well as any unscheduled principal prepayments on the underlying mortgage loans. The mortgage-backed

securities purchased by the Fund may include bonds and notes issued or guaranteed by U.S. government-sponsored entities, such as the Federal National Mortgage Association (Fannie Mae) and the Federal Home Loan Mortgage Corporation (Freddie Mac) and by the Government National Mortgage Association (Ginnie Mae). The Fund currently focuses on mortgage-backed securities issued or guaranteed by Fannie Mae and Freddie Mac.

Government agency or instrumentality issues have different levels of credit support. Ginnie Mae pass-through mortgage certificates are backed by the full faith and credit of the U.S. government. U.S. government-sponsored entities, such as Fannie Mae and Freddie Mac, may be chartered by Acts of Congress, but their securities are neither issued nor guaranteed by the U.S. government. Although the U.S. government has provided financial support to Fannie Mae and Freddie Mac, no assurance can be given that the U.S. government will continue to do so. Accordingly, securities issued by Fannie Mae and Freddie Mac may involve a greater risk of non-payment of principal and interest. Investors should remember that guarantees of timely repayment of principal and interest do not apply to the market prices and yields of the securities or to the net asset value or performance of the Fund, which will vary with changes in interest rates and other market conditions.

Periodic interest rate adjustments may help keep the prices of ARMS relatively stable when compared with the prices of fixed-rate securities, which generally fall when interest rates rise. As a result, the Fund may participate in increases in interest rates resulting in higher current yields, but with less fluctuation in net asset value than a fund invested in comparable fixed-rate securities. Adjustable-rate securities, however, frequently limit the maximum amount by which the interest rate may change up or down. The Fund, therefore, may not benefit from increases in interest rates if prevailing interest rates exceed a security's maximum allowable periodic or lifetime limits. During periods of falling interest rates, the interest rates on these securities may reset downward, resulting in a lower yield for the Fund.

The Fund may invest up to 20% of its net assets in other securities, including fixed-rate mortgage-backed securities and mortgage-backed securities, including non-agency CMOs, issued by a private entity. The Fund may also invest in direct obligations of the U.S. government or of its agencies, instrumentalities or sponsored enterprises, such as Treasury bills, bonds or notes, and in repurchase agreements collateralized by U.S. government or government agency securities.

Principal Risks

You could lose money by investing in the Fund. Mutual fund shares are not deposits or obligations of, or guaranteed or endorsed by, any bank, and are not insured by the Federal Deposit Insurance Corporation, the Federal Reserve Board, or any other agency of the U.S. government.

Interest Rate When interest rates rise, debt security prices generally fall. The opposite is also generally true: debt security prices rise when interest rates fall. Interest rate changes are influenced by a number of factors, including government policy, monetary policy, inflation expectations, perceptions of risk, and supply of and demand for bonds. In general, securities with longer maturities or durations are more sensitive to interest rate changes.

Prepayment Prepayment risk occurs when a debt security can be repaid in whole or in part prior to the security's maturity and the Fund must reinvest the proceeds it receives, during periods of declining interest rates, in securities that pay a lower rate of interest. Also, if a security has been purchased at a premium, the value of the premium would be lost in the event of prepayment. Prepayments generally increase when interest rates fall.

Adjustable Rate Securities Because changes in interest rates on adjustable rate securities may lag behind changes in market rates, the value of such securities may decline during periods of rising interest rates until their interest rates reset to market rates. During periods of declining interest rates, because the interest rates on adjustable rate securities generally reset downward, their market value is unlikely to rise to the same extent as the value of comparable fixed rate securities.

LIBOR Transition The Fund invests in financial instruments that may have floating or variable rate calculations for payment obligations or financing terms based on the London Interbank Offered Rate (LIBOR), which is the benchmark interest rate at which major global banks lend to one another in the international interbank market for short-term loans. It was originally anticipated that LIBOR would be discontinued by the end of 2021 and would cease to be published after that time. Although many LIBOR rates were phased out at the end of 2021 as originally intended, a selection of widely used USD LIBOR rates will continue to be published until June 2023 in order to assist with the transition to an alternative rate. The impact of the discontinuation of LIBOR and the transition to an alternative rate on the Fund's portfolio remains uncertain. There can be no guarantee that financial instruments that transition to an alternative reference rate will retain the same value or liquidity as they would otherwise have had.

Mortgage Securities Mortgage securities differ from conventional debt securities because principal is paid back periodically over the life of the security rather than at maturity. The Fund may receive unscheduled payments of principal due to voluntary prepayments, refinancings or foreclosures on the underlying mortgage loans. Because of prepayments, mortgage securities may be less effective than some other types of debt securities as a means of "locking in" long-term interest rates and may have less potential for capital appreciation during periods of falling interest rates. A reduction in the anticipated rate of principal prepayments, especially during periods of rising interest rates, may increase or extend the effective maturity of mortgage securities, making them more sensitive to interest rate changes, subject to greater price volatility, and more susceptible than some other debt securities to a decline in market value when interest rates rise.

Extension   Some debt securities, particularly mortgage-backed securities, are subject to the risk that the debt security’s effective maturity is extended because calls or prepayments are less or slower than anticipated, particularly when interest rates rise. The market value of such security may then decline and become more interest rate sensitive.

Market The market values of securities or other investments owned by the Fund will go up or down, sometimes rapidly or unpredictably. The market value of a security or other investment may be reduced by market activity or other results of supply and demand unrelated to the issuer. This is a basic risk associated with all investments. When there are more sellers than buyers, prices tend to fall. Likewise, when there are more buyers than sellers, prices tend to rise.

The current global outbreak of the novel strain of coronavirus, COVID-19, has resulted in market closures and dislocations, extreme volatility, liquidity constraints and increased trading costs. Efforts to contain the spread of COVID-19 have resulted in global travel restrictions and disruptions of healthcare systems, business operations and supply chains, layoffs, volatility in consumer demand for certain products, defaults and credit ratings downgrades, and other significant economic impacts. The effects of COVID-19 have impacted global economic activity across many industries and may heighten other pre-existing political, social and economic risks, locally or globally. The full impact of the COVID-19 pandemic is unpredictable and may adversely affect the Fund’s performance.

Income The Fund's distributions to shareholders may decline when prevailing interest rates fall, when the Fund experiences defaults on debt securities it holds or when the Fund realizes a loss upon the sale of a debt security.

Credit An issuer of debt securities may fail to make interest payments or repay principal when due, in whole or in part. Changes in an issuer's financial strength or in a security's or government's credit rating may affect a security's value.

While securities issued by Ginnie Mae are backed by the full faith and credit of the U.S. government, not all securities of the various U.S. government agencies are, including those of Fannie Mae and Freddie Mac. Accordingly, securities issued by Fannie Mae and Freddie Mac may involve a risk of non-payment of principal and interest.

Management The Fund is subject to management risk because it is an actively managed investment portfolio. The Fund's investment manager applies investment techniques and risk analyses in making investment decisions for the Fund, but there can be no guarantee that these decisions will produce the desired results.

Performance

The following bar chart and table provide some indication of the risks of investing in the Fund. The bar chart shows changes in the Fund's performance from year to year for Class A shares. The table shows how the Fund's average annual returns for 1 year, 5 years, 10 years or since inception, as applicable, compared with those of a broad measure of market performance. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. You can obtain updated performance information at franklintempleton.com or by calling (800) DIAL BEN/342-5236.

Sales charges are not reflected in the bar chart, and if those charges were included, returns would be less than those shown.

Class A Annual Total Returns

Best Quarter:	2020, Q2	2.42%
Worst Quarter:	2020, Q1	-1.51%

Average Annual Total Returns

(figures reflect sales charges)

For periods ended December 31, 2021

		1 Year	5 Years	10 Years	Since Inception
Adjustable Government Securities Fund - Class A
	Return before taxes	-2.46%	0.28%	0.27%	—
	Return after taxes on distributions	-2.81%	-0.56%	-0.43%	—
	Return after taxes on distributions and sale of Fund shares	-1.45%	-0.15%	-0.09%	—
Franklin Adjustable U.S. Government Securities Fund - Class A1		-2.44%	0.40%	0.37%	—
Franklin Adjustable U.S. Government Securities Fund - Class C		-1.76%	0.30%	0.09%	—
Franklin Adjustable U.S. Government Securities Fund - Class R6		-0.01%	1.10%	—	0.85%	1
Franklin Adjustable U.S. Government Securities Fund - Advisor Class		-0.13%	0.96%	0.73%	—
Bloomberg US Government (1-2 Year) Index (index reflects no deduction for fees, expenses or taxes)		-0.32%	1.50%	0.98%	—
1.	Since inception September 20, 2013.

Historical performance for Class A1 shares prior to their inception is based on the performance of Class A shares.

The 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. Actual after-tax returns depend on an investor's tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown only for Class A and after-tax returns for other classes will vary.

Investment Manager

Franklin Advisers, Inc. (Advisers)

Portfolio Manager

Paul Varunok
Senior Vice President of Advisers and portfolio manager of the Fund since 2003.

Purchase and Sale of Fund Shares

You may purchase or redeem shares of the Fund on any business day online through our website at franklintempleton.com, by mail (Franklin Templeton Investor Services, P.O. Box 997151, Sacramento, CA 95899-7151), or by telephone at (800) 632-2301. For Class A, A1 and C, the minimum initial purchase for most accounts is $1,000 (or $25 under an automatic investment plan). Class R6 and Advisor Class are only available to certain qualified investors and the minimum initial investment will vary depending on the type of qualified investor, as described under "Your Account — Choosing a Share Class — Qualified Investors — Class R6" and "— Advisor Class" in the Fund's prospectus. There is no minimum investment for subsequent purchases.

Taxes

The Fund’s distributions are generally taxable to you as ordinary income, unless you are investing through a tax-deferred arrangement, such as a 401(k) plan or an individual retirement account, in which case your distributions would generally be taxed when withdrawn from the tax-deferred account.

Payments to Broker-Dealers and
Other Financial Intermediaries

If you purchase shares of 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 financial advisor or visit your financial intermediary's website for more information.

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