Fidelity® Long-Term Treasury Bond Index Fund (formerly Spartan^® Long-Term Treasury Bond Index Fund)

Class/Ticker

Investor/FLBIX Premium (formerly Fidelity Advantage^®)/FLBAX

Summary Prospectus

April 29, 2017

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 and other information about the fund (including the fund's SAI) online at www.fidelity.com/funddocuments. You can also get this information at no cost by calling 1-800-FIDELITY or by sending an e-mail request to fidfunddocuments@fidelity.com. The fund's prospectus and SAI dated April 29, 2017 are incorporated herein by reference.

245 Summer Street, Boston, MA 02210

Fund Summary

Fund/Class:
Fidelity® Long-Term Treasury Bond Index Fund
/Investor, Premium

Investment Objective

The fund seeks a high level of current income.

Fee Table

The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

Shareholder fees

(fees paid directly from your investment)

None

Annual Operating Expenses

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

	Investor Class	Premium Class
Management fee	0.05%	0.05%
Distribution and/or Service (12b-1) fees	None	None
Other expenses	0.14%^(a)	0.04%
Total annual operating expenses	0.19%	0.09%

(a) Adjusted to reflect current fees

This example helps compare the cost of investing in the fund with the cost of investing in other funds.

Let's say, hypothetically, that the annual return for shares of the fund is 5% and that your shareholder fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:

	Investor Class	Premium Class
1 year	$19	$9
3 years	$61	$29
5 years	$107	$51
10 years	$243	$115

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 operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 40% of the average value of its portfolio.

Principal Investment Strategies

Normally investing at least 80% of assets in securities included in the Bloomberg Barclays U.S. Long Treasury Bond Index.

Normally maintaining a dollar-weighted average maturity of 10 years or more.

Using statistical sampling techniques based on duration, maturity, interest rate sensitivity, security structure, and credit quality to attempt to replicate the returns of the Bloomberg Barclays U.S. Long Treasury Bond Index using a smaller number of securities.

Principal Investment Risks

Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease.

Prepayment. The ability of an issuer of a debt security to repay principal prior to a security's maturity can cause greater price volatility if interest rates change.

Issuer-Specific Changes. The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole. A decline in the credit quality of an issuer or a provider of credit support or a maturity-shortening structure for a security can cause the price of a security to decrease.

Correlation to Index. The performance of the fund and its index may vary somewhat due to factors such as fees and expenses of the fund, transaction costs, sample selection, regulatory restrictions, and timing differences associated with additions to and deletions from its index.

Passive Management Risk. The fund is managed with a passive investment strategy, attempting to track the performance of an unmanaged index of securities, regardless of the current or projected performance of the fund’s index or of the actual securities included in the index. This differs from an actively managed fund, which typically seeks to outperform a benchmark index. As a result, the fund’s performance could be lower than actively managed funds that may shift their portfolio assets to take advantage of market opportunities or lessen the impact of a market decline or a decline in the value of one or more issuers.

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. Unlike individual debt securities, which typically pay principal at maturity, the value of an investment in the fund will fluctuate. You could lose money by investing in the fund.

Performance

The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time. The index description appears in the Additional Index Information section of the prospectus. Past performance (before and after taxes) is not an indication of future performance.

Visit www.fidelity.com for more recent performance information.

Year-by-Year Returns

During the periods shown in the chart for Investor Class:	Returns	Quarter ended
Highest Quarter Return	24.97%	September 30, 2011
Lowest Quarter Return	(12.11)%	December 31, 2016
Year-to-Date Return	1.56%	March 31, 2017

Average Annual Returns

After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. After-tax returns for Investor Class are shown in the table below and after-tax returns for other classes will vary. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.

For the periods ended December 31, 2016	Past 1 year	Past 5 years	Past 10 years
Investor Class - Return Before Taxes	1.10%	2.30%	6.43%
Return After Taxes on Distributions	0.00%	1.08%	5.00%
Return After Taxes on Distributions and Sale of Fund Shares	0.67%	1.22%	4.51%
Premium Class - Return Before Taxes	1.12%	2.40%	6.53%
Bloomberg Barclays U.S. Long Treasury Bond Index (reflects no deduction for fees, expenses, or taxes)	1.33%	2.52%	6.68%

Investment Adviser

Fidelity Management & Research Company (FMR) (the Adviser) is the fund's manager. Fidelity Investments Money Management, Inc. (FIMM) and other investment advisers serve as sub-advisers for the fund.

Portfolio Manager(s)

Brandon Bettencourt (co-manager) has managed the fund since May 2014.

Jay Small (co-manager) has managed the fund since April 2015.

Purchase and Sale of Shares

You may buy or sell shares through a Fidelity^® brokerage or mutual fund account, through a retirement account, or through an investment professional. You may buy or sell shares in various ways:

Internet

www.fidelity.com

Phone

Fidelity Automated Service Telephone (FAST^®) 1-800-544-5555

To reach a Fidelity representative 1-800-544-6666

Mail

Additional purchases:

Fidelity Investments
P.O. Box 770001
Cincinnati, OH 45277-0003

Redemptions:

Fidelity Investments
P.O. Box 770001
Cincinnati, OH 45277-0035

TDD- Service for the Deaf and Hearing Impaired

1-800-544-0118

The price to buy one share is its net asset value per share (NAV). Shares will be bought at the NAV next calculated after your investment is received in proper form.

The price to sell one share is its NAV. Shares will be sold at the NAV next calculated after an order is received in proper form.

The fund is open for business each day the New York Stock Exchange (NYSE) is open.

Initial Purchase Minimum - Investor Class	$2,500
For Fidelity® Simplified Employee Pension-IRA, Keogh, and Investment Only Retirement accounts	$500
Through regular investment plans in Fidelity® Traditional IRAs, Roth IRAs, and Rollover IRAs (requires monthly purchases of $200 until fund balance is $2,500)	$200
Initial Purchase Minimum - Premium Class	$10,000

The fund may waive or lower purchase minimums in other circumstances.

Tax Information

Distributions you receive from the fund are subject to federal income tax and generally will be taxed as ordinary income or capital gains, and may also be subject to state or local taxes, unless you are investing through a tax-advantaged retirement account (in which case you may be taxed later, upon withdrawal of your investment from such account).

Payments to Broker-Dealers and Other Financial Intermediaries

The fund, the Adviser, Fidelity Distributors Corporation (FDC), and/or their affiliates may pay intermediaries, which may include banks, broker-dealers, retirement plan sponsors, administrators, or service-providers (who may be affiliated with the Adviser or FDC), for the sale of fund shares and related services. These payments may create a conflict of interest by influencing your intermediary and your investment professional to recommend the fund over another investment. Ask your investment professional or visit your intermediary's web site for more information.

Current regulations allow Fidelity to send a single copy of shareholder documents for Fidelity^® funds, such as prospectuses, annual and semiannual reports, and proxy materials, to certain mutual fund customers whom we believe are members of the same family who share the same address. For certain types of accounts, we will not send multiple copies of these documents to you and members of your family who share the same address. Instead, we will send only a single copy of these documents. This will continue for as long as you are a shareholder, unless you notify us otherwise. If at any time you choose to receive individual copies of any documents, please call 1-800-544-8544. We will begin sending individual copies to you within 30 days of receiving your call.

FDC is a member of the Securities Investor Protection Corporation (SIPC). You may obtain information about SIPC, including the SIPC brochure, by visiting www.sipc.org or calling SIPC at 202-371-8300.

Any third-party marks that may appear above are the marks of their respective owners.

1.925681.110

LBX-SUM-0417