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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington D.C. 20549

FORM 10-K/A

Amendment No. 1

x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended October 31, 2010

or

¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from             to             

Commission File Number 001-34164

CurrencyShares^® Singapore Dollar Trust

Sponsored by Rydex Specialized Products LLC,

d/b/a Rydex Investments

(Exact name of registrant as specified in its charter)

(301) 296-5100

(Registrant’s telephone number, including area code)

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  ¨    No  x

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.    Yes  ¨    No  x

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  ¨    No  ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.  x

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer or a smaller reporting company. See definitions of “large accelerated filer,” “accelerated filer,” “non-accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):    Large accelerated filer   ¨    Accelerated filer  ¨    Non-accelerated filer  ¨    Smaller reporting company  x

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes  ¨    No  x

During the fiscal period ended October 31, 2010, none of the registrant’s common stock was held by non-affiliates of the registrant.

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EXPLANATORY NOTE

This Amendment No. 1 on Form 10-K/A to the Annual Report on Form 10-K for the year ended October 31, 2010 of CurrencyShares^® Singapore Dollar Trust, which Form 10-K was originally filed with the Securities and Exchange Commission on January 14, 2011, is being filed for the purpose of amending Item 15 in order to (i) include the report of our prior independent registered public accounting firm, (ii) amend the Exhibit Index and (iii) file certain exhibits as indicated in the Exhibit Index. Other than providing updates to the cover page, amending Item 15 and filing updated exhibits and certifications, no other changes have been made to the original Form 10-K. This Amendment No. 1 does not reflect any subsequent events occurring after the filing of the original Form 10-K or modify or update in any way disclosures made in the original filing.

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PART IV

Financial Statements

See Index to Financial Statements on Page F-1 for a list of the financial statements being filed as a part of this report. Schedules have been omitted since they are either not required, not applicable or the information has otherwise been included.

Exhibits

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CurrencyShares^® Singapore Dollar Trust

Financial Statements as of October 31, 2010

Index

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Report of Independent Registered Public Accounting Firm

To the Shareholders of CurrencyShares^® Singapore Dollar Trust:

In our opinion, the balance sheet as of October 31, 2009 and the related statements of income and comprehensive income, of changes in shareholders’ equity and of cash flows for the year ended October 31, 2009 and for the period August 8, 2008 (date of inception) through October 31, 2008 present fairly, in all material respects, the financial position of CurrencyShares^® Singapore Dollar Trust (the “Trust”) at October 31, 2009, and the results of its operations and its cash flows for the year ended October 31, 2009 and for the period August 8, 2008 (date of inception) through October 31, 2008, in conformity with accounting principles generally accepted in the United States of America. These financial statements are the responsibility of the Trust’s management. Our responsibility is to express an opinion on these financial statements based on our audits. We conducted our audits of these statements in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.

/s/ PricewaterhouseCoopers LLP

Baltimore, Maryland

January 14, 2010

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Report of Independent Registered Public Accounting Firm

To the Shareholders of CurrencyShares^® Singapore Dollar Trust:

We have audited the accompanying statement of financial condition of CurrencyShares^® Singapore Dollar Trust (the “Trust”) at October 31, 2010 and the related statements of income and comprehensive income, changes in shareholders’ equity, and cash flows for the year then ended. These financial statements are the responsibility of the Trust’s management. Our responsibility is to express an opinion on these financial statements based on our audit.

We conducted our audit in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements. An audit also includes assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. We believe that our audit provides a reasonable basis for our opinion.

In our opinion, the financial statements referred to above present fairly, in all material respects, the financial position of CurrencyShares^® Singapore Dollar Trust at October 31, 2010 and the and the results of its operations and its cash flows for the year then ended, in conformity with U.S. generally accepted accounting principles.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States), the effectiveness of CurrencyShares^® Singapore Dollar Trust’s internal control over financial reporting as of October 31, 2010, based on criteria established in Internal Control-Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO), and our report dated January 14, 2011 expressed an unqualified opinion thereon.

/s/ Ernst & Young LLP

McLean, VA

January 14, 2011

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CurrencyShares^® Singapore Dollar Trust

Statements of Financial Condition

See Notes to Financial Statements.

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CurrencyShares^® Singapore Dollar Trust

Statements of Income and Comprehensive Income

See Notes to Financial Statements.

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CurrencyShares^® Singapore Dollar Trust

Statements of Changes in Shareholder’s Equity

See Notes to Financial Statements.

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CurrencyShares^® Singapore Dollar Trust

Statements of Cash Flows

See Notes to Financial Statements.

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CurrencyShares^® Singapore Dollar Trust

Notes to Financial Statements

The CurrencyShares^® Singapore Dollar Trust (the “Trust”) was formed under the laws of the State of New York on August 7, 2008. On August 8, 2008, Rydex Specialized Products LLC d/b/a “Rydex Investments” (the “Sponsor”) deposited 100 Singapore Dollars in the Trust’s primary deposit account held by JPMorgan Chase Bank, N.A., London Branch (the “Depository”). The Sponsor is a Delaware limited liability company whose sole member is Rydex Advisors II, LLC (also d/b/a “Rydex Investments”). The Sponsor is responsible for, among other things, overseeing the performance of The Bank of New York Mellon (the “Trustee”) and the Trust’s principal service providers, including the preparation of financial statements. The Trustee is responsible for the day-to-day administration of the Trust.

The investment objective of the Trust is for the Trust’s shares (the “Shares”) to reflect the price of the Singapore Dollar plus accrued interest less the Trust’s expenses and liabilities. The Shares are intended to provide investors with a simple, cost-effective means of gaining investment benefits similar to those of holding Singapore Dollar. The Trust’s assets primarily consist of Singapore Dollars on demand deposit in two deposit accounts maintained by the Depository: a primary deposit account which may earn interest and a secondary deposit account which does not earn interest. The secondary deposit account is used to account for any interest that may be received and paid out on creations and redemptions of 50,000 Shares (“Baskets”). The secondary account is also used to account for interest earned, if any, on the primary deposit account, pay Trust expenses and distribute any excess interest to holders of Shares (“Shareholders”) on a monthly basis.

The accompanying audited financial statements were prepared in accordance with accounting principles generally accepted in the United States.

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of the assets, liabilities and disclosures of contingent liabilities at the date of the financial statements, the reported amounts of revenue and expenses during the period and the evaluation of subsequent events through the issuance date of the financial statements. Actual results could differ from those estimates.

The Trustee will calculate the Trust’s net asset value (“NAV”) each business day, as described in Note 4. For NAV calculation purposes, Singapore Dollars deposits (cash) are translated at the Closing Spot Rate, which is the U.S. Dollar (“USD”)/Singapore Dollars exchange rate as determined by WM/Reuters at 4:00 PM (London time) on each day that NYSE Arca is open for regular trading.

The functional currency of the Trust is the Singapore Dollars in accordance with generally accepted accounting standards. For financial statement reporting purposes, the U.S. Dollar is the reporting currency. As a result, the financial records of the Trust are translated from Singapore Dollars to USD. The Closing Spot Rate on the last day of the period is used for translation in the statements of financial condition. The average Closing Spot Rate for the period is used for translation in the statements of income and comprehensive income and the statement of cash flows. Any currency translation adjustment is included in comprehensive income.

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The Trust is treated as a “grantor trust” for federal income tax purposes and, therefore, no provision for federal income taxes is required. Interest, gains and losses are passed through to the Shareholders.

Shareholders generally will be treated, for U.S. federal income tax purposes, as if they directly owned a pro-rata share of the assets held in the Trust. Shareholders also will be treated as if they directly received their respective pro-rata portion of the Trust’s income, if any, and as if they directly incurred their respective pro-rata portion of the Trust’s expenses. The acquisition of Shares by a U.S. Shareholder as part of a creation of a Basket will not be a taxable event to the Shareholder.

The Sponsor’s fee accrues daily and is payable monthly. For U.S. federal income tax purposes, an accrual-basis U.S. Shareholder generally will be required to take into account as an expense its allocable portion of the USD-equivalent of the amount of the Sponsor’s fee that is accrued on each day, with such USD-equivalent being determined by the currency exchange rate that is in effect on the respective day. To the extent that the currency exchange rate on the date of payment of the accrued amount of the Sponsor’s fee differs from the currency exchange rate in effect on the day of accrual, the U.S. Shareholder will recognize a currency gain or loss for U.S. federal income tax purposes.

The Trust does not expect to generate taxable income except for interest income (if any) and gain (if any) upon the sale of Singapore Dollars. A non-U.S. Shareholder generally will not be subject to U.S. federal income tax with respect to gain recognized upon the sale or other disposition of Shares, or upon the sale of Singapore Dollars by the Trust, unless: (1) the non-U.S. Shareholder is an individual and is present in the United States for 183 days or more during the taxable year of the sale or other disposition, and the gain is treated as being from United States sources; or (2) the gain is effectively connected with the conduct by the non-U.S. Shareholder of a trade or business in the United States.

A non-U.S. Shareholder’s portion of any interest income earned by the Trust generally will not be subject to U.S. federal income tax unless the Shares owned by such non-U.S. Shareholder are effectively connected with the conduct by the non-U.S. Shareholder of a trade or business in the United States.

Interest on the primary deposit account, if any, accrues daily as earned and is received on a monthly basis.

To the extent that the interest earned by the Trust, if any, exceeds the sum of the Sponsor’s fee for the prior month plus other Trust expenses, if any, the Trust will distribute, as a dividend (herein referred to as dividends or distributions), the excess interest earned in Singapore Dollars effective on the first business day of the subsequent month. The Trustee will direct that the excess Singapore Dollars be converted into USD at a prevailing market rate and the Trustee will distribute the USD as promptly as practicable to Shareholders on a pro-rata basis (in accordance with the number of Shares that they own).

Singapore Dollar principal deposits are held in a Singapore Dollar-denominated, interest-bearing demand account. For the year ended October 31, 2010, there were no principal deposits and no principal redemptions resulting in an ending Singapore Dollar balance of 100. This equates to 77 USD. For the year ended October 31, 2009, there were no principal deposits and no principal redemptions resulting in an ending Singapore Dollar balance of 100. This equates to 72 USD. For the period from August 8, 2008 (date of inception) to October 31, 2008, there were Singapore Dollar principal deposits of 100 and no Singapore Dollar principal redemptions resulting in an ending Singapore Dollar principal balance of 100. This equates to 67 USD.

Shares are classified as “redeemable” for financial statement purposes, since they are subject to redemption. Shares are issued and redeemed continuously in Baskets in exchange for Singapore Dollars. Individual investors cannot

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purchase or redeem Shares in direct transactions with the Trust. Only Authorized Participants (as defined below) may place orders to create and redeem Baskets. An Authorized Participant is a participant of the Depository Trust Company (“DTC”) that is a registered broker-dealer or other institution eligible to settle securities transactions through the book-entry facilities of DTC and which has entered into a contractual arrangement with the Trust and the Sponsor governing, among other matters, the creation and redemption process. Authorized Participants may redeem their Shares at any time in Baskets.

Due to expected continuing creations and redemptions of Baskets and the three-day period for settlement of each creation or redemption, the Trust reflects Shares created as a receivable. Shares redeemed are reflected as a liability on the trade date. Outstanding Shares are reflected at a redemption value, which is the NAV per Share at the period end date. Adjustments to redeemable capital shares at redemption value are recorded against retained earnings, or, in the absence of retained earnings, by charges against the cumulative translation adjustment.

Activity in redeemable capital Shares is as follows:

The Trustee will calculate the Trust’s NAV each business day. To calculate the NAV, the Trustee will subtract the Sponsor’s accrued fee through the previous day from the Singapore Dollars held by the Trust (including all unpaid interest accrued through the preceding day) and calculate the value of the Singapore Dollars in USD based upon the Closing Spot Rate. If, on a particular evaluation day, the Closing Spot Rate has not been determined and announced by 6:00 PM (London time), then the most recent Closing Spot Rate will be used to determine the NAV of the Trust unless the Trustee, in consultation with the Sponsor, determines that such price is inappropriate to use as the basis for the valuation. If the Trustee and the Sponsor determine that the most recent Closing Spot Rate is not an appropriate basis for valuation of the Trust’s Singapore Dollars, they will determine an alternative basis for the valuation. The Trustee also determines the NAV per Share, which equals the NAV of the Trust divided by the number of outstanding Shares. Shares deliverable under a purchase order are considered outstanding for purposes of determining NAV per Share; Shares deliverable under a redemption order are not considered outstanding for this purpose.

The Sponsor’s fee will accrue daily at an annual nominal rate of 0.40% of the Singapore Dollars in the Trust (including all unpaid interest but excluding unpaid fees, each as accrued through the immediately preceding day) and will be paid monthly.

The Sponsor assumes and pays the following administrative and marketing expenses incurred by the Trust: the Trustee’s monthly fee, NYSE Arca listing fees, SEC registration fees, typical maintenance and transaction fees of the Depository, printing and mailing costs, audit fees and expenses, up to $100,000 per year in legal fees and expenses, and applicable license fees.

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In certain exceptional cases the Trust will pay for some expenses in addition to the Sponsor’s fee. These exceptions include expenses not assumed by the Sponsor (i.e., expenses other than those identified in the preceding paragraph), taxes and governmental charges, expenses and costs of any extraordinary services performed by the Trustee or the Sponsor on behalf of the Trust or action taken by the Trustee or the Sponsor to protect the Trust or the interests of Shareholders, indemnification of the Sponsor under the Depositary Trust Agreement, and legal expenses in excess of $100,000 per year.

The Sponsor is a related party of the Trust. The Sponsor oversees the performance of the Trustee and the Trust’s principal service providers, including the preparation of financial statements, but does not exercise day-to-day oversight over the Trustee or the Trust’s service providers.

All of the Trust’s assets are Singapore Dollars, which creates a concentration risk associated with fluctuations in the price of the Singapore Dollar. Accordingly, a decline in the Singapore Dollar to USD exchange rate will have an adverse effect on the value of the Shares. Factors that may have the effect of causing a decline in the price of the Singapore Dollar include national debt levels and trade deficits, domestic and foreign inflation rates, domestic and foreign interest rates, investment and trading activities of institutions and global or regional political, economic or financial events and situations. Substantial sales of Singapore Dollars by the official sector (central banks, other governmental agencies and related institutions that buy, sell and hold Singapore Dollars as part of their reserve assets) could adversely affect an investment in the Shares.

All of the Trust’s Singapore Dollars are held by the Depository. Accordingly, a risk associated with the concentration of the Trust’s assets in accounts held by a single financial institution exists and increases the potential for loss by the Trust and the Shareholders in the event that the Depository becomes insolvent.

Under the Trust’s organizational documents, the Sponsor is indemnified against any liability or expense it incurs without negligence, bad faith or willful misconduct on its part. The Trust’s maximum exposure under these arrangements is unknown, as this would involve future claims that may be made against the Trust that have not yet occurred.

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SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized in the City of Rockville, State of Maryland, on March 10, 2011.

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities* and on the dates indicated.