UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 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): July 29, 2014

EXPRESS SCRIPTS HOLDING COMPANY

(Exact Name of Registrant as Specified in its Charter)

Registrant’s telephone number including area code: 314-996-0900

No change since last report

(Former Name or Address, if Changed Since Last Report)

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 July 29, 2014, Express Scripts Holding Company (the “Company”) issued a press release with respect to its results of operations for the period ended June 30, 2014, guidance for third quarter and fiscal year 2014 and future business outlook. The press release is attached hereto as Exhibit 99.1 and incorporated herein by reference.

The information contained in this Current Report on Form 8-K, including the accompanying Exhibit 99.1, is being furnished pursuant to Item 2.02 and Item 7.01 of Form 8-K and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section. The information contained in this Current Report on Form 8-K, including the accompanying Exhibit 99.1, shall not be incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, whether made before or after the date hereof, except as shall be expressly set forth by specific reference in such a filing.

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 thereunto duly authorized.

Exhibit 99.1

Contact:

Cathy Smith, Chief Financial Officer

Jamie Kates, Director, Investor Relations

(314) 684-6521

investor.relations@express-scripts.com

Express Scripts Announces 2nd Quarter Results;

Narrows 2014 Guidance Range; Maintains Mid-Point

ST. LOUIS, July 29, 2014 — Express Scripts Holding Company (Nasdaq: ESRX) announced 2014 second quarter net income attributable to Express Scripts stockholders of $515.2 million, or $0.67 per diluted share. Adjusted earnings per diluted share, as detailed in Table 4, was $1.23 for the second quarter.¹

“We are well positioned to serve our clients with scale, alignment and innovative solutions to lower costs, manage trend and to improve the health outcomes of our members,” stated George Paz, chairman and chief executive officer. “We are using our scale in formulary management, regulatory compliance and personalized care through our Therapeutic Resource Centers, to control cost and provide a safe, convenient pharmacy experience. Our focus on reducing patients’ costs while improving their health outcomes, together with our business model, aligns our objectives with those of our clients.”

Second Quarter 2014 Review

The expected roll-off of UnitedHealth Group (“UNH”) claims was completed by the end of 2013. The following table compares the second quarter 2014 and 2013 operating results from continuing operations excluding and including UNH (also see Tables 7 and 8):

As expected and similar to the second quarter of last year, revenue of $129.4 million related to a large client contract was realized in the second quarter of 2014 due to the structure of the contract. Second quarter net cash flow provided by operating activities was $735.5 million and the Company repurchased 29.9 million shares of common stock for $2,191.6 million during the quarter, leaving 42.9 million shares available under the current repurchase program.

2014 Guidance

The Company narrowed its adjusted earnings per diluted share guidance from a range of $4.82 to $4.94 to a range of $4.84 to $4.92, which maintains the mid-point of $4.88. The new guidance range reflects year over year growth of 17% to 19% excluding UNH (see Table 8) or growth of 12% to 14% including UNH. Additional details on this guidance and items excluded from this range can be found in Table 6.

The Company expects the following for the third quarter of 2014 – (see Table 6):

Future Business Outlook

The acquisition of Medco closed in April of 2012 and Express Scripts embarked on a journey to build one of the most consequential companies in healthcare. During the following two years, the Company has focused relentlessly on moving to a single platform in a complex and changing environment. This integration activity resulted in isolated challenges for some clients. In addition, when two large companies merge together, it creates changes to people, processes and systems. For example, certain account management teams experienced turnover; often these relationships are key to retaining clients.

Historically, the Company has a strong track record of successful acquisitions resulting in combining the best of both systems and processes, and building new leadership and solidifying account teams. Clients are naturally going to evaluate alternatives and test the market. Express Scripts took advantage of this dynamic in the past when competitors merged. Competitors are attempting to take advantage of this situation now. As Express Scripts exits two years of integration, the Company is emerging as a stronger PBM and is well-positioned for the future.

Due to the dynamics of the market, the retention rate for 2015 is expected to be in the range of 92-93%. This retention rate combined with strong organic growth and new sales will result in expected claims volume slightly down to down 1.5% in 2015. We expect that future organic earnings growth will come from several drivers, of which script volume is just one component. Other drivers include generic conversions, specialty pharmacy, formulary management, clinical programs and home delivery. All of these levers will drive EBITDA and earnings growth in the future.

Express Scripts has built the most advanced, best positioned PBM in the industry and service excellence has been a top priority. The Company has taken clear and specific steps to improve both the client and patient experience and continues to invest in people, processes and systems to enhance the services provided and optimize every patient touch point. Express Scripts’ service metrics indicate that it is delivering at or above strong historical levels.

“Service is a very important component of the PBM offering,” stated Tim Wentworth, president. “We believe that in addition to our size, scale and innovation, our investment in and commitment to client and patient service positions Express Scripts well for future growth.”

About Express Scripts

Express Scripts manages more than a billion prescriptions each year for tens of millions of patients. On behalf of our clients – employers, health plans, unions and government health programs – we make the use of prescription drugs safer and more affordable. Express Scripts uniquely combines three capabilities – behavioral sciences, clinical specialization and actionable data – to create Health Decision Science^SM, our innovative approach to help individuals make the best drug choices, pharmacy choices and health choices. Better decisions mean healthier outcomes.

Headquartered in St. Louis, Express Scripts provides integrated pharmacy benefit management services, including network-pharmacy claims processing, home delivery, specialty benefit management, benefit-design consultation, drug-utilization review, formulary management, and medical and drug data analysis services. The company also distributes a full range of biopharmaceutical products and provides extensive cost-management and patient-care services.

For more information, visit Lab.Express-Scripts.com or follow @ExpressScripts on Twitter.

SAFE HARBOR STATEMENT

This press release contains forward-looking statements, including, but not limited to, our 2014 guidance and our statements related to the Company’s plans, objectives, expectations (financial and otherwise) or intentions. Actual results may differ significantly from those projected or suggested in any forward-looking statements. Factors that may impact these forward-looking statements can be found in the Management’s Discussion and Analysis of Financial Condition and Results of Operations section of the Company’s Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (“SEC”) on July 29, 2014 and Item 1A – “Risk Factors” in the Company’s Annual Report on Form 10-K filed with the SEC on February 20, 2014. A copy of these documents can be found at the Investor Information section of Express Scripts’ web site at http://www.express-scripts.com/corporate.

We do not undertake any obligation to release publicly any revisions to such forward-looking statements to reflect events or circumstances after the date hereof or to reflect the occurrence of unanticipated events.

EXPRESS SCRIPTS HOLDING COMPANY

Unaudited Consolidated Statement of Operations

EXPRESS SCRIPTS HOLDING COMPANY

Unaudited Consolidated Balance Sheet

EXPRESS SCRIPTS HOLDING COMPANY

Unaudited Consolidated Statement of Cash Flows

Table 1

Express Scripts Holding Company Unaudited Consolidated Selected Information

(in millions)

Note: See Appendix for Footnotes

Table 2

Calculation of Express Scripts Holding Company Adjusted Gross Profit and SG&A - Continuing Operations

(in millions)

Note: See Appendix for Footnotes

The Company is providing adjusted gross profit and adjusted selling, general and administrative expenses (both of which are non-GAAP financial measures), in each case, excluding the impact of amortization of intangible assets and transaction and integration costs in order to compare the underlying financial performance to prior periods.

Table 3

Express Scripts Holding Company EBITDA Reconciliation

(in millions, except per claim data)

The following is a reconciliation of net income from continuing operations attributable to Express Scripts to EBITDA from continuing operations attributable to Express Scripts. The Company believes net income is the most directly comparable measure calculated under U.S. GAAP.

Note: See Appendix for Footnotes

The Company is providing EBITDA and adjusted EBITDA excluding the impact of certain charges (both of which are non-GAAP financial measures) in order to compare the underlying financial performance to prior periods.

EBITDA from continuing operations is earnings before other income (expense), interest, taxes, depreciation and amortization, or alternatively calculated as operating income from continuing operations plus depreciation and amortization less non-controlling interest. EBITDA from continuing operations is presented because it is a widely accepted indicator of a company’s ability to service indebtedness and is frequently used to evaluate a company’s performance. EBITDA from continuing operations, however, should not be considered as an alternative to net income from continuing operations, as a measure of operating performance, as an alternative to cash flow, as a measure of liquidity or as a substitute for any other measure computed in accordance with accounting principles generally accepted in the United States. In addition, our definition and calculation of EBITDA from continuing operations may not be comparable to that used by other companies.

Adjusted EBITDA from continuing operations per adjusted claim is a supplemental measurement used by analysts and investors to help evaluate overall operating performance. We have calculated adjusted EBITDA from continuing operations excluding transaction and integration costs recorded each year, as these charges are not considered an indicator of ongoing company performance. Adjusted EBITDA from continuing operations per adjusted claim is calculated by dividing adjusted EBITDA from continuing operations by the adjusted claim volume for the period. This measure is used as an indicator of EBITDA performance on a per-unit basis. Adjusted EBITDA from continuing operations, and as a result, adjusted EBITDA from continuing operations per adjusted claim, are each affected by the changes in claim volumes between retail and home delivery, the relative representation of brand-name, generic and specialty pharmacy drugs, as well as the level of efficiency in the business.

Table 4

Calculation of Express Scripts Holding Company Adjusted Diluted EPS

Note: See Appendix for Footnotes

The Company is providing diluted EPS from continuing operations attributable to Express Scripts and diluted EPS from continuing operations attributable to Express Scripts excluding the impact of transaction, integration and certain other costs and amortization of intangible assets (which are non-GAAP financial measures) in order to compare the underlying financial performance to prior periods.

Table 5

Calculation of Express Scripts Holding Company Adjusted Net Income and Adjusted Effective Income Tax Rate

(in millions)

Note: See Appendix for Footnotes.

The Company is providing adjusted net income attributable to Express Scripts, net of tax and adjusted effective income tax rate attributable to Express Scripts excluding the impact of certain items and amortization of intangible assets (which are non-GAAP financial measures) in order to compare the underlying financial performance to prior periods.

Table 5A

Calculation of Express Scripts Holding Company Adjusted Net Income and Adjusted Effective Income Tax Rate for Continuing Operations

(in millions)

Note: See Appendix for Footnotes.

The Company is providing adjusted net income attributable to Express Scripts, net of tax and adjusted effective income tax rate attributable to Express Scripts excluding the impact of certain items and amortization of intangible assets (which are non-GAAP financial measures) in order to compare the underlying financial performance to prior periods.

Table 6

Express Scripts Holding Company 2014 Guidance Information

The full-year impact of integration and certain other costs has yet to be determined. Accordingly, the Company is unable to include these charges in the list of GAAP items not included in guidance for 2014 full-year and third quarter adjusted EPS, adjusted selling, general and administrative, adjusted EBITDA and adjusted EBITDA per adjusted claim or to provide a reconciliation to the corresponding GAAP measure. These integration expenses are expected to end in the second half of 2014. 2014 Adjusted EPS will exclude amortization of intangible assets per diluted share in the range of $1.41 to $1.45.

Table 7

Express Scripts Holding Company Operating Results Excluding UnitedHealth Group (“UNH”)

(Amounts in millions except per share and per claim data)

The Company is providing operating results excluding UNH (which are non-GAAP financial measures) in order to compare the underlying financial performance to prior periods.

Amounts presented as continuing operations.

Table 8

Express Scripts Holding Company - UnitedHealth Group (“UNH”) Contribution by Quarter

(Amounts in millions except per share and per claim data)

The Company is providing UNH 2013 operating results by quarter and adjusted earnings per share excluding UNH (both of which are non-GAAP financial measures) in order to compare the underlying financial performance to prior periods.

Amounts presented as continuing operations.

Appendix

Footnotes

Amortization of legacy Express Scripts intangible assets include amounts in both revenues and selling, general and administrative expense.

Revenue amortization is related to the customer contract with WellPoint which commenced upon closing of the NextRx acquisition in 2009. Under U.S. GAAP, amortization of intangibles that arise in connection with consideration given to a customer by a vendor is characterized as a reduction of revenues. Intangible amortization of $28.5 million ($17.7 million and $17.3 million net of tax in 2014 and 2013, respectively) is included as a reduction to revenue for the three months ended June 30, 2014 and 2013. Intangible amortization of $57.0 million ($35.3 million and $34.6 million net of tax in 2014 and 2013, respectively) is included as a reduction to revenue for the six months ended June 30, 2014 and 2013.

Other legacy Express Scripts intangible amortization of $9.4 million ($5.9 million net of tax) and $10.2 million ($6.2 million net of tax) for the three months ended June 30, 2014 and 2013, respectively, is included in selling, general and administrative expense. Other legacy Express Scripts intangible amortization of $18.8 million ($11.7 million net of tax) and $20.3 million ($12.3 million net of tax) for the six months ended June 30, 2014 and 2013, respectively, is included in selling, general and administrative expense.

Amortization of intangible assets related to the acquisition of Medco Health Solutions, Inc. (“Medco”) of $399.9 million ($248.1 million net of tax) and $466.9 million ($283.4 million net of tax) for the three months ended June 30, 2014 and 2013, respectively, is included in selling, general and administrative expense. Amortization of intangible assets related to the acquisition of Medco of $800.1 million ($495.4 million net of tax) and $929.7 million ($564.3 million net of tax) for the six months ended June 30, 2014 and 2013, respectively, is included in selling, general and administrative expense.

Costs of $108.6 million ($67.4 million net of tax) and $36.6 million ($22.2 million net of tax) primarily composed of integration-related activities, are included in gross profit for the three months ended June 30, 2014 and 2013, respectively. Costs of $216.4 million ($134.0 million net of tax) and $81.1 million ($49.2 million net of tax) primarily composed of integration-related activities, are included in gross profit for the six months ended June 30, 2014 and 2013, respectively.

Costs of $129.8 million ($80.5 million net of tax) and $105.3 million ($63.9 million net of tax) primarily composed of professional fees, integration-related activities and severance costs, including stock compensation, are included in selling, general and administrative expense for the three months ended June 30, 2014 and 2013, respectively. Costs of $255.1 million ($158.0 million net of tax) and $218.9 million ($132.8 million net of tax) primarily composed of professional fees, integration-related activities and severance costs, including stock compensation, are included in selling, general and administrative expense for the six months ended June 30, 2014 and 2013, respectively.

The Company recorded a net benefit of $3.5 million ($2.1 million net of tax) within selling, general and administrative expenses for the three months ended March 31, 2013 in conjunction with a final settlement related to the strategic decision to exit various businesses.