UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of report (Date of earliest event reported): May 14, 2013

Shutterfly, Inc.

(Exact Name of Registrant as Specified in Charter)

Delaware

(State or Other Jurisdiction of Incorporation)

(650) 610-5200

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

On May 20, 2013, Shutterfly, Inc. (the “Company”) completed its private offering of $300.0 million in aggregate principal amount of the Company’s 0.25% Convertible Senior Notes due 2018 (the “Notes”). The aggregate principal amount of the Notes sold reflects the exercise in full by the initial purchasers of the Notes (the “Initial Purchasers”) of their option to purchase up to an additional $30.0 million in aggregate principal amount of the Notes. The Notes were issued pursuant to an Indenture, dated May 20, 2013 (the “Indenture”) between the Company and Wells Fargo Bank, National Association, a national banking association, as trustee. The Indenture includes customary terms and covenants, including certain events of default after which the Notes may be due and payable immediately. A copy of the Indenture (including the form of the Note) is attached as an exhibit to this report and is incorporated herein by reference (and this description is qualified in its entirety by reference to such document).

The Notes are the Company’s unsecured senior obligations. The Notes will mature on May 15, 2018, unless repurchased or converted in accordance with their terms prior to such date. The Notes will pay interest semi-annually at a rate of 0.25% per year, payable in arrears on May 15 and November 15 of each year, beginning on November 15, 2013. Prior to December 15, 2017, the Notes will be convertible at the option of the holders only upon satisfaction of certain conditions and during certain periods, and thereafter, at any time until the close of business on the second scheduled trading day immediately preceding the maturity date. Upon conversion, the Notes may be settled in shares of the Company’s common stock, cash or a combination of cash and shares of the Company’s common stock, at the Company’s option. Holders of the Notes will have the right to require the Company to repurchase all or some of their Notes at 100% of their principal amount, plus any accrued and unpaid interest, upon the occurrence of a fundamental change (as defined in the Indenture). In addition, upon the occurrence of a make-whole fundamental change (as defined in the Indenture), the Company may be required to increase the conversion rate for the Notes converted in connection with such a make-whole fundamental change. The Notes will be convertible at an initial conversion rate of 15.5847 shares of the Company’s common stock per $1,000 principal amount of the Notes, which is equivalent to an initial conversion price of approximately $64.17 per share of common stock, and is subject to adjustment under the terms of the Notes. The Company may not redeem the notes prior to maturity.

In connection with the pricing of the Notes on May 14, 2013, the Company entered into privately negotiated convertible note hedge transactions (together, the “Base Convertible Note Hedge Transactions”) with each of Morgan Stanley & Co. International plc, Credit Suisse International, Citibank, N.A., and Bank of America, N.A. (together, the “Option Counterparties”). In addition, on May 15, 2013, the Company entered into additional convertible note hedge transactions (the “Additional Convertible Note Hedge Transactions,” and, together with the Base Convertible Note Hedge Transactions, the “Convertible Note Hedge Transactions”) with each of the Option Counterparties. The Convertible Note Hedge Transactions cover, subject to customary anti-dilution adjustments substantially similar to those applicable to the Notes, the number of shares of the Company’s common stock underlying the Notes, as described below. On May 14, 2013 and May 15, 2013, the Company also entered into separate, privately negotiated warrant transactions (the “Warrant Transactions”) with each of the Option Counterparties initially relating to the number of shares of the Company’s common stock underlying the Convertible Note Hedge Transactions, subject to customary anti-dilution adjustments. Subject to certain conditions, the Company may settle the warrants in cash or on a net-share basis.

The Convertible Note Hedge Transactions are expected generally to reduce the potential dilution and/or offset the cash payments the Company is required to make in excess of the principal amount upon conversion of the Notes in the event that the market price of the Company’s common stock is greater than the strike price of the Convertible Note Hedge Transactions, which initially corresponds to the initial conversion price of the Notes. The Warrant Transactions could separately have a dilutive effect if the market price of the Company’s common stock exceeds the strike price of the Warrant Transactions, unless the Company elects, subject to certain conditions, to settle the Warrant Transactions in cash. The strike price of the Warrant Transactions will initially be $83.1775 per share of the Company’s common stock and is subject to certain adjustments under the terms of the Warrant Transactions. Copies of the confirmations relating to the Convertible Note Hedge Transactions and Warrant Transactions are attached as exhibits to this report and are incorporated by reference (and this description is qualified in its entirety by reference to such documents).

The net proceeds from the sale of the Notes, including net proceeds from the exercise in full by the Initial Purchasers of their option to purchase up to an additional $30.0 million in aggregate principal amount of the Notes, were approximately $291.5 million, after deducting the Initial Purchasers’ discounts and commissions and the estimated offering and expenses payable by it. The Company used approximately $18.0 million of the net proceeds to pay the cost of the Convertible Note Hedge Transactions, after taking into account the proceeds to the Company of the Warrant Transactions, and approximately $30.0 million of the net proceeds to repurchase shares of the Company’s common stock. The Company intends to use the remainder of the net proceeds to fund acquisitions and other strategic transactions and for general corporate purposes.

The Convertible Note Hedge Transactions and the Warrant Transactions are separate transactions, in each case, entered into by the Company with the Option Counterparties, and are not part of the terms of the Notes and will not affect any holder’s rights under the Notes. Holders of the Notes will not have any rights with respect to the Convertible Note Hedge Transactions or the Warrant Transactions.

The Company entered into the Warrant Transactions with the Option Counterparties in reliance on the exemption from registration provided by Section 4(2) of the Securities Act. The Warrant Transactions and the shares of the Company’s common stock issuable upon exercise of the warrants comprising the Warrant Transactions, if any, have not been registered under the Securities Act and may not be offered or sold in the United States absent registration or an applicable exemption from registration requirements.

The foregoing description of the Convertible Note Hedge Transactions and the Warrant Transactions is qualified in its entirety by the copies of the confirmations for the Convertible Note Hedge Transactions and the Warrant Transactions which are attached as Exhibits 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 10.10, 10.11, 10.12, 10.13, 10.14, 10.15 and 10.16 and incorporated herein by reference.

The information set forth under Item 1.01 of this Current Report on Form 8-K is incorporated by reference.

The information set forth under Item 1.01 of this Current Report on Form 8-K is incorporated herein by reference.

The Company offered and sold the Notes to the Initial Purchasers in reliance on the exemption from registration provided by Section 4(2) of the Securities Act of 1933, as amended (the “Securities Act”), and for resale by the Initial Purchasers to qualified institutional buyers pursuant to the exemption from registration provided by Rule 144A under the Securities Act. The Company relied on these exemptions from registration based in part on representations made by the Initial Purchasers in the Purchase Agreement.

The Notes and the shares of the Company’s common stock issuable upon conversion of the Notes, if any, have not been registered under the Securities Act and may not be offered or sold in the United States absent registration or an applicable exemption from registration requirements.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

EXHIBIT INDEX