0000028540 2023-09-29 2023-09-29 0000028540 fmr:FidelitySeriesCommodityStrategyFund-PROMember fmr:S000042145Member 2023-09-29 2023-09-29 0000028540 fmr:FidelitySeriesCommodityStrategyFund-PROMember fmr:S000042145Member fmr:C000130874Member 2023-09-29 2023-09-29 0000028540 fmr:FidelitySeriesCommodityStrategyFund-PROMember fmr:S000042145Member fmr:ReturnBeforeTaxesMember fmr:C000130874Member 2023-09-29 2023-09-29 0000028540 fmr:FidelitySeriesCommodityStrategyFund-PROMember fmr:S000042145Member rr:AfterTaxesOnDistributionsMember fmr:C000130874Member 2023-09-29 2023-09-29 0000028540 fmr:FidelitySeriesCommodityStrategyFund-PROMember fmr:S000042145Member rr:AfterTaxesOnDistributionsAndSalesMember fmr:C000130874Member 2023-09-29 2023-09-29 0000028540 fmr:FidelitySeriesCommodityStrategyFund-PROMember fmr:S000042145Member fmr:IndexDJ010Member 2023-09-29 2023-09-29 0000028540 fmr:FidelityCommodityStrategyFund-RetailPROMember fmr:S000055837Member 2023-09-29 2023-09-29 0000028540 fmr:FidelityCommodityStrategyFund-RetailPROMember fmr:S000055837Member fmr:C000175832Member 2023-09-29 2023-09-29 0000028540 fmr:FidelityCommodityStrategyFund-RetailPROMember fmr:S000055837Member fmr:ReturnBeforeTaxesMember fmr:C000175832Member 2023-09-29 2023-09-29 0000028540 fmr:FidelityCommodityStrategyFund-RetailPROMember fmr:S000055837Member rr:AfterTaxesOnDistributionsMember fmr:C000175832Member 2023-09-29 2023-09-29 0000028540 fmr:FidelityCommodityStrategyFund-RetailPROMember fmr:S000055837Member rr:AfterTaxesOnDistributionsAndSalesMember fmr:C000175832Member 2023-09-29 2023-09-29 0000028540 fmr:FidelityCommodityStrategyFund-RetailPROMember fmr:S000055837Member fmr:IndexDJ010Member 2023-09-29 2023-09-29 0000028540 fmr:FidelitySAIInflation-FocusedFund-PROMember fmr:S000063840Member 2023-09-29 2023-09-29 0000028540 fmr:FidelitySAIInflation-FocusedFund-PROMember fmr:S000063840Member fmr:C000206762Member 2023-09-29 2023-09-29 0000028540 fmr:FidelitySAIInflation-FocusedFund-PROMember fmr:S000063840Member fmr:ReturnBeforeTaxesMember fmr:C000206762Member 2023-09-29 2023-09-29 0000028540 fmr:FidelitySAIInflation-FocusedFund-PROMember fmr:S000063840Member rr:AfterTaxesOnDistributionsMember fmr:C000206762Member 2023-09-29 2023-09-29 0000028540 fmr:FidelitySAIInflation-FocusedFund-PROMember fmr:S000063840Member rr:AfterTaxesOnDistributionsAndSalesMember fmr:C000206762Member 2023-09-29 2023-09-29 0000028540 fmr:FidelitySAIInflation-FocusedFund-PROMember fmr:S000063840Member fmr:IndexDJ010Member 2023-09-29 2023-09-29 iso4217:USD pure 485BPOS 2023-07-31 false 0000028540 N-1A Fidelity Oxford Street Trust Fund Summary Fund: Fidelity® Series Commodity Strategy Fund Investment Objective Fidelity® Series Commodity Strategy Fund seeks to provide investment returns that correspond to the performance of the commodities market. Fee Table The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. Shareholder fees 0 Annual Operating Expenses 0.0000 0 0.0000 0.0000 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 the 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: 0 0 0 0 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 0% of the average value of its portfolio. 0 Principal Investment Strategies Normally investing in commodity-linked derivative instruments, short-term investment-grade debt securities, cash, and cash equivalents.Investing up to 25% of assets in a wholly-owned subsidiary organized under the laws of the Cayman Islands that invests in commodity-linked total return swaps based on the value of commodities or commodities indexes and in other commodity-linked derivative instruments.Managing the fund to track an index chosen to represent the commodities market, as well as short-term investment-grade debt securities, which as of July 31, 2023 was the Bloomberg Commodity Index.Investing in domestic and foreign issuers.Engaging in commodity-linked derivatives transactions that have a leveraging effect on the fund.Investing in Fidelity's Central funds (specialized investment vehicles used by Fidelity® funds to invest in particular security types or investment disciplines) consistent with the asset classes discussed above. Principal Investment Risks Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease. Foreign Exposure. Foreign markets can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market. Financial Services Exposure. Changes in government regulation and interest rates and economic downturns can have a significant negative effect on issuers in the financial services sector, including the price of their securities or their ability to meet their payment obligations. Subsidiary Risk. Investment in Geode Series Commodity Return Cayman Ltd., an unregistered subsidiary, is not subject to the investor protections of the Investment Company Act of 1940 (1940 Act) and is subject to the risks associated with investing in derivatives and commodity-linked investing in general. Changes in tax and other laws could negatively affect investments in the subsidiary. 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. Leverage Risk. Leverage can increase market exposure, magnify investment risks, and cause losses to be realized more quickly. Commodity-Linked Investing. The value of commodities and commodity-linked investments may be affected by the performance of the overall commodities markets as well as weather, political, tax, and other regulatory and market developments. Commodity-linked investments may be more volatile and less liquid than the underlying commodity, instruments, or measures. Commodity Futures. Investments in commodity futures contracts are also subject to the risk of the failure of any of the exchanges on which the fund's positions trade or of its clearinghouses or counterparties. In addition, certain commodity exchanges limit fluctuations in certain futures contract prices during a single day by regulations referred to as "daily price fluctuation limits" or "daily limits." Under such daily limits, during a single trading day no trades may be executed at prices beyond the daily limit. If triggered, these limits could prevent the fund from liquidating unfavorable positions and subject the fund to losses or prevent it from entering into desired trades during the particular trading day. 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. You could lose money by investing in the fund. 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.  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. 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. Past performance (before and after taxes) is not an indication of future performance. www.fidelity.com Year-by-Year Returns -0.1000 -0.1755 -0.2527 0.1107 0.0092 -0.1110 0.0741 -0.0311 0.2713 0.1498    Highest Quarter Return 0.2494 2022-03-31    Lowest Quarter Return -0.2332 2020-03-31    Year-to-Date Return -0.0811 2023-06-30 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. 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. 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. 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. Return Before Taxes 0.1498 0.0622 -0.0172 Return After Taxes on Distributions -0.1110 -0.0242 -0.0583 Return After Taxes on Distributions and Sale of Fund Shares 0.0949 0.0131 -0.0280 Bloomberg Commodity Index 0.1609 0.0644 -0.0128 Fund Summary Fund: Fidelity® Commodity Strategy Fund Investment Objective Fidelity® Commodity Strategy Fund seeks to provide investment returns that correspond to the performance of the commodities market. Fee Table The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. Shareholder fees 0 Annual Operating Expenses 0.0040 0 0.0022 0.0002 0.0064 Differs from the ratios of expenses to average net assets in the Financial Highlights section of the prospectus because of acquired fund fees and expenses. 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 the 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: 65 205 357 798 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 0% of the average value of its portfolio. 0 Principal Investment Strategies Normally investing in commodity-linked derivative instruments, short-term investment-grade debt securities, cash, and cash equivalents.Investing up to 25% of assets in a wholly-owned subsidiary organized under the laws of the Cayman Islands that invests in commodity-linked total return swaps based on the value of commodities or commodities indexes and in other commodity-linked derivative instruments.Managing the fund to track an index chosen to represent the commodities market, as well as short-term investment-grade debt securities, which as of July 31, 2023 was the Bloomberg Commodity Index.Investing in domestic and foreign issuers.Engaging in commodity-linked derivatives transactions that have a leveraging effect on the fund.Investing in Fidelity's Central funds (specialized investment vehicles used by Fidelity® funds to invest in particular security types or investment disciplines) consistent with the asset classes discussed above. Principal Investment Risks Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease. Foreign Exposure. Foreign markets can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market. Financial Services Exposure. Changes in government regulation and interest rates and economic downturns can have a significant negative effect on issuers in the financial services sector, including the price of their securities or their ability to meet their payment obligations. Subsidiary Risk. Investment in Geode Commodity Strategy Cayman Ltd., an unregistered subsidiary, is not subject to the investor protections of the Investment Company Act of 1940 (1940 Act) and is subject to the risks associated with investing in derivatives and commodity-linked investing in general. Changes in tax and other laws could negatively affect investments in the subsidiary. 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. Leverage Risk. Leverage can increase market exposure, magnify investment risks, and cause losses to be realized more quickly. Commodity-Linked Investing. The value of commodities and commodity-linked investments may be affected by the performance of the overall commodities markets as well as weather, political, tax, and other regulatory and market developments. Commodity-linked investments may be more volatile and less liquid than the underlying commodity, instruments, or measures. Commodity Futures. Investments in commodity futures contracts are also subject to the risk of the failure of any of the exchanges on which the fund's positions trade or of its clearinghouses or counterparties. In addition, certain commodity exchanges limit fluctuations in certain futures contract prices during a single day by regulations referred to as "daily price fluctuation limits" or "daily limits." Under such daily limits, during a single trading day no trades may be executed at prices beyond the daily limit. If triggered, these limits could prevent the fund from liquidating unfavorable positions and subject the fund to losses or prevent it from entering into desired trades during the particular trading day. 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. You could lose money by investing in the fund. 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.  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. 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. Past performance (before and after taxes) is not an indication of future performance. www.fidelity.com Year-by-Year Returns -0.1168 0.0689 -0.0384 0.2629 0.1403    Highest Quarter Return 0.2417 2022-03-31    Lowest Quarter Return -0.2353 2020-03-31    Year-to-Date Return -0.0829 2023-06-30 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. 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. 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. 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. Return Before Taxes 0.1403 0.0551 0.0601 Return After Taxes on Distributions -0.0258 -0.0033 0.0072 Return After Taxes on Distributions and Sale of Fund Shares 0.0871 0.0177 0.0240 Bloomberg Commodity Index 0.1609 0.0644 0.0697 2017-05-30 Fund Summary Fund: Fidelity® SAI Inflation-Focused Fund Investment Objective Fidelity® SAI Inflation-Focused Fund seeks total return. Fee Table The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. Shareholder fees 0 Annual Operating Expenses 0.0038 0 0.0001 0.0039 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 the 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: 40 125 219 493 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 61% of the average value of its portfolio. 0.61 Principal Investment Strategies Normally investing in commodity-linked derivative instruments, cash, and cash equivalents.Investing up to 25% of assets in a wholly-owned subsidiary organized under the laws of the Cayman Islands that invests in commodity-linked derivative instruments including commodity-linked notes; total return swaps, options, and forward contracts based on the value of commodities or commodities indexes; and commodity futures.Investing in domestic and foreign issuers.Engaging in commodity-linked derivatives transactions that have a leveraging effect on the fund.The fund may invest in inflation-protected debt securities issued by the U.S. Treasury, U.S. Government agencies and instrumentalities other than the U.S. Treasury, and by other entities such as corporations and foreign governments, and/or other types of investment-grade debt securities that are not inflation protected.Allocating assets across different market sectors and maturities.Analyzing the credit quality of the issuer, security-specific features, current and potential future valuation, and trading opportunities to select investments.Engaging in transactions that have a leveraging effect on the fund, including investments in derivatives - such as swaps (interest rate, total return, and credit default) and futures contracts - and forward-settling securities, to adjust the fund's risk exposure.Investing in Fidelity's Central funds (specialized investment vehicles used by Fidelity® funds to invest in particular security types or investment disciplines) consistent with the asset classes discussed above. Principal Investment Risks Interest Rate Changes. Interest rate increases can cause the price of a debt security to decrease. Foreign Exposure. Foreign markets can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market. Financial Services Exposure. Changes in government regulation and interest rates and economic downturns can have a significant negative effect on issuers in the financial services sector, including the price of their securities or their ability to meet their payment obligations. Subsidiary Risk. Investment in Geode SAI Inflation-Focused Cayman Ltd., an unregistered subsidiary, is not subject to the investor protections of the Investment Company Act of 1940 (1940 Act) and is subject to the risks associated with investing in derivatives and commodity-linked investing in general. Changes in tax and other laws could negatively affect investments in the subsidiary. 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. Leverage Risk. Leverage can increase market exposure, magnify investment risks, and cause losses to be realized more quickly. Investing for Inflation Protection. Increases in real interest rates can cause the price of inflation-protected debt securities to decrease. Interest payments on inflation-protected debt securities can be unpredictable. Commodity-Linked Investing. The value of commodities and commodity-linked investments may be affected by the performance of the overall commodities markets as well as weather, political, tax, and other regulatory and market developments. Commodity-linked investments may be more volatile and less liquid than the underlying commodity, instruments, or measures. Commodity Futures. Investments in commodity futures contracts are also subject to the risk of the failure of any of the exchanges on which the fund's positions trade or of its clearinghouses or counterparties. In addition, certain commodity exchanges limit fluctuations in certain futures contract prices during a single day by regulations referred to as "daily price fluctuation limits" or "daily limits." Under such daily limits, during a single trading day no trades may be executed at prices beyond the daily limit. If triggered, these limits could prevent the fund from liquidating unfavorable positions and subject the fund to losses or prevent it from entering into desired trades during the particular trading day. 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. You could lose money by investing in the fund. Unlike individual debt securities, which typically pay principal at maturity, the value of an investment in the fund will fluctuate. 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.  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. Prior to September 29, 2023, the fund operated under certain different investment policies. The fund's historical performance may not represent its current investment policies. Visit www.fidelity.com for more recent performance information. 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. Past performance (before and after taxes) is not an indication of future performance. www.fidelity.com Year-by-Year Returns 0.0984 0.0146 0.3259 0.0910    Highest Quarter Return 0.2291 2022-03-31    Lowest Quarter Return -0.2296 2020-03-31    Year-to-Date Return -0.0889 2023-06-30 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. 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. 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. 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. Return Before Taxes 0.0910 0.1204 Return After Taxes on Distributions 0.0434 0.0697 Return After Taxes on Distributions and Sale of Fund Shares 0.0557 0.0718 Bloomberg Commodity Index 0.1609 0.1057 2018-12-20 Effective October 2, 2023, the fund will begin comparing its performance to the Bloomberg Commodity 50/50 Petroleum and ex-Petroleum Index rather than the Bloomberg Commodity Index because the Bloomberg Commodity 50/50 Petroleum and ex-Petroleum Index conforms more closely to the fund's investment policies.  AThe fund may invest in a wholly-owned subsidiary, Geode Commodity Strategy Cayman Ltd. The subsidiary has entered into a separate contract with Geode Capital Management, LLC (Geode) for the management of its portfolio pursuant to which the subsidiary does not pay Geode a fee. The subsidiary pays certain other expenses including custody fees. BDiffers from the ratios of expenses to average net assets in the Financial Highlights section of the prospectus because of acquired fund fees and expenses. AFrom May 30, 2017. AFrom December 20, 2018.