Term Sheet

dated June 18, 2009

Filed pursuant to Rule 433

Registration File No. 333-152892

Supplementing the Preliminary

Prospectus Supplements

dated June 16, 2009

(To Prospectus dated June 15, 2009)

Company Name:

Assured Guaranty Ltd., a Bermuda company (“AGO”)

Ticker / Exchange for Common Shares:

AGO / The New York Stock Exchange (“NYSE”)

Trade Date:

June 18, 2009

Settlement Date:

June 24, 2009

Common Share Offering

Title of Securities:

Common shares, par value $0.01 per share, of AGO

Registration format:

SEC Registered

Shares Offered and Sold:

38,500,000 (or a total of 44,275,000 if the underwriters exercise in full their option to purchase up to 5,775,000 additional common shares of AGO)

Overallotment Option:

5,775,000 common shares of AGO

Public Offering Price:

$11.00 per share / approximately $423,500,000 million total (excluding the underwriters’ option to purchase up to 5,775,000 additional common shares of AGO)

Proceeds, before expenses, to AGO:

$404,442,500 million (excluding the underwriters’ option to purchase up to 5,775,000 additional common shares of AGO)

Use of Proceeds:

AGO intends to use $363.8 million of the net proceeds of the Common Share Offering to pay the cash purchase price for the acquisition of Financial Security Assurance Holdings Ltd. (the “Acquisition”). AGO intends to use the remaining net proceeds from the Common Share Offering and the net proceeds from the Equity Units Offering to pay cash in lieu of Assured common shares, including Excess Shares, that AGO would otherwise deliver as part of the purchase price for the Acquisition.

Joint Book-Running Managers:

Merrill Lynch, Pierce, Fenner & Smith Incorporated and Deutsche Bank Securities Inc

Co-Managers:

Wachovia Capital Markets, LLC

KeyBanc Capital Markets Inc.

UBS Securities LLC

PNC Capital Markets LLC

Piper Jaffray & Co.

Keefe, Bruyette & Woods, 

Inc. Sandler O’Neill & Partners, L.P.

Fox-Pitt Kelton Cochran Caronia Waller (USA) LLC

Samuel A. Ramirez & Company, Inc.

Equity Units Offering

Title of Securities:

Equity Units (initially in the form of Corporate Units)

Registration format:

SEC Registered

Aggregate Offering Amount:

$150.0 million (or a total of $172.5 million if the underwriters exercise in full their option to purchase up to 450,000 additional Corporate Units)

Overallotment Option:

$22.5 million

Stated Amount per Equity Unit:

$50

Proceeds, before expenses, to AGO:

$145.5 million (excluding underwriters option to purchase up to 450,000 additional Corporate Units)

Total Distribution Rate:

8.50%

Reference Price:

$11.00 per common share of AGO, the Public Offering Price per share in the Common Share

Offering

Threshold Appreciation Price:

$12.93, a 17.5% appreciation over the Reference Price

Minimum Settlement Rate (as defined):

3.8685 shares of AGO common stock (subject to adjustment)

Maximum Settlement Rate (as defined):

4.5455 shares of AGO common stock (subject to adjustment)

Purchase Contract Settlement Date:

June 1, 2012

Note Issuer:

Assured Guaranty US Holdings Inc. (“AGUSH,” and together with AGO, the “Issuers”)

Note Guarantor:

AGO

Note Coupon:

8.50%

Note Maturity Date:

June 1, 2014, unless the notes have been previously redeemed in connection with a special event redemption or the maturity date has been modified upon a successful remarketing

Note Coupon Payment Dates:

March 1, June 1, September 1 and December 1

First Note Coupon:

September 1, 2009

Early Remarketing:

AGUSH may, at its option, elect to remarket the notes underlying the Corporate Units on any remarketing date occurring during the period beginning on December 1, 2011 and ending on May 1, 2012, unless the notes have been previously redeemed in connection with a special event redemption or have been previously successfully remarketed.

Final Remarketing Period:

May 24, 2012 to May 29, 2012

Additional Notes:

The Issuers may, without notice to or the consent of the then existing holders of the notes, issue additional notes ranking equally and ratably with the notes in all respects except for the issue price, issue date and the payment of interest accruing prior to the issue date of the additional notes or the first payment of interest following the issue date of the additional notes. The additional notes will be consolidated and form a single series with the notes offered in this offering and will have the same terms as to status, redemption or otherwise as the notes offered in this offering.

Use of Proceeds:

AGO intends to use $363.8 million of the net proceeds of the concurrent Common Share Offering to pay the cash purchase price for the Acquisition. AGO intends to use the remaining net proceeds from the Common Share Offering and the net proceeds from the Equity Units Offering to pay cash in lieu of Assured common

shares, including Excess Shares, that AGO would otherwise deliver as part of the purchase price for the Acquisition.

AGO currently intends to use the proceeds from the settlement of the purchase contracts to repay debt as soon as practicable following such settlement, and AGO has agreed not to use such proceeds to repurchase AGO’s common shares.

CUSIP for the Corporate Units:

G0585R 122

ISIN for the Corporate Units:

BMG0585R1227

CUSIP for the Treasury Units:

G0585R 114

ISIN for the Treasury Units:

BMG0585R1144

CUSIP for the Notes:

04621W AB6

ISIN for the Notes:

US04621WAB63

Allocation of the Purchase Price:

At the time of issuance, the fair market value of the applicable ownership interest in the notes will be $49.19 (or 98.4% of the issue price of a Corporate Unit) and the fair market value of each purchase contract will be $0.81 (or 1.6% of the issue price of a Corporate Unit).

Comparable Yield on the Notes:

10.1%

Book-Running Manager:

Merrill Lynch, Pierce, Fenner & Smith Incorporated

Co-Manager:

Citigroup Global Markets Inc.

Creating Treasury Units:

As described in the preliminary prospectus supplement, if the Treasury portfolio has replaced the notes underlying the Corporate Units, holders of Corporate Units will have the right, at any time on or prior to the second business day immediately preceding the purchase contract settlement date, to substitute Treasury securities for the applicable ownership interests in the Treasury portfolio underlying the Corporate Unit, but holders of Corporate Units can only make this substitution in integral multiples of 16,000 Corporate Units (or such other number of Corporate Units as may be determined by the remarketing agent upon a successful remarketing of notes if the reset effective date is not a regular quarterly interest payment date).

Recreating Corporate Units:

As described in the preliminary prospectus supplement, if the Treasury portfolio has replaced the notes underlying the Corporate Units, holders of Treasury Units will have the right, at any time on or prior to the second business day immediately

preceding the purchase contract settlement date, to substitute the applicable ownership interests in the Treasury portfolio for the Treasury securities that were a component of the Treasury Units, but holders of Treasury Units can only make this substitution in integral multiples of 16,000 Treasury Units (or such other number of Treasury Units as may be determined by the remarketing agent upon a successful remarketing of notes if the reset effective date is not a regular quarterly interest payment date).

Early Settlement:

A purchase contract can be settled for cash prior to the purchase contract settlement date at a settlement rate of 3.8685 shares per Equity Unit.

Early Settlement Upon a Fundamental Change:

Upon the occurrence of a fundamental change (as defined), a holder of a purchase contract will have the right to accelerate and settle such purchase contract early at the “fundamental change settlement rate,” which will depend on the share price in such fundamental change and the date such fundamental change occurs.

The following table sets forth the hypothetical common share price and the fundamental change settlement rate per Stated Amount of Equity Units:

Stock

Effective Date

Price

June 24, 2009

June 1, 2010

June 1, 2011

June 1, 2012

$

6.00

5.6343

5.3504

5.0133

4.5455

$

8.00

5.0413

4.8692

4.7094

4.5455

$

10.00

4.6717

4.5278

4.4041

4.5455

$

11.00

4.5476

4.4079

4.2794

4.5455

$

12.00

4.4535

4.3172

4.1829

4.1667

$

12.93

4.3872

4.2549

4.1185

3.8685

$

15.00

4.2896

4.1691

4.0413

3.8685

$

17.50

4.2272

4.1231

4.0138

3.8685

$

20.00

4.1933

4.1031

4.0065

3.8685

$

25.00

4.1548

4.0810

3.9930

3.8685

$

30.00

4.1266

4.0603

3.9766

3.8685

$

40.00

4.0794

4.0221

3.9508

3.8685

$

50.00

4.0432

3.9936

3.9344

3.8685

$

60.00

4.0163

3.9734

3.9235

3.8685

$

75.00

3.9878

3.9526

3.9125

3.8685

$

100.00

3.9583

3.9316

3.9015

3.8685