1 Non-GAAP measure - see definitions at the end of this release.

FALLS CHURCH, Va. – June 5, 2018 – Northrop Grumman Corporation (NYSE: NOC) announced today that the U.S. Federal Trade Commission (FTC) has cleared Northrop Grumman’s proposed acquisition of Orbital ATK Inc. The FTC’s Bureau of Competition has completed its review of the merger, and the Premerger Notification Office has informed the company that the waiting period under the HSR Act has terminated, allowing the companies to complete the merger. As part of that clearance, the FTC issued a decision and order providing for solid rocket motors to be available on a non-discriminatory basis under specified circumstances and under processes defined in the order. The company expects to complete the transaction after market close tomorrow and is issuing the following updated guidance. This updated guidance assumes the completion of the transaction tomorrow.

• Northrop Grumman now expects 2018 sales of approximately $30 billion, EPS of $16.20 to $16.45 and free cash flow 1 of $2.3 to $2.6 billion

Updated 2018 Guidance

2018 financial guidance reflects the company's judgment based on the information available to the company at the time of this release. The government budget and appropriations processes can impact our customers, programs and financial results. Government budgets, appropriations, including the timing of appropriations, and the occurrence of continuing resolutions and government shutdowns can impact the company's ability to achieve 2018 guidance.

Updated 2018 guidance reaffirms Northrop Grumman stand-alone guidance provided on April 25, 2018 and reflects the expected results of Innovation Systems for the remainder of the year. Updated guidance reflects a partial year of acquisition-related purchased intangibles amortization of approximately $175 million; this estimate is subject to the completion of purchase accounting and other post-closing activities. Free cash flow guidance for 2018 also reflects an expected $250 million discretionary pension contribution.

About Northrop Grumman

Northrop Grumman is a leading global security company providing innovative systems, products and solutions in autonomous systems, cyber, C4ISR, strike, and logistics and modernization to customers worldwide. Please visit news.northropgrumman.com and follow us on Twitter, @NGCNews , for more information.

Cautionary Statement Regarding Forward-Looking Statements

Statements in this press release, other than statements of historical fact, constitute “forward-looking” information within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “will,” “anticipate,” “expect,” “intend,” “plan,” “believe,” “estimate,” and similar expressions generally identify these forward-looking statements. Forward-looking statements include, among other things, statements regarding the benefits and implications of the Orbital ATK acquisition. These forward-looking statements speak only as of the date when made, and Northrop Grumman undertakes no obligation to update or revise any forward-looking statements after the date of this press release except as required by applicable law. Forward-looking statements are not guarantees of future performance and inherently involve a wide range of risks and uncertainties that are difficult to predict. Actual results may differ materially from those described or implied in these statements based on a number of factors. A discussion of these risks and uncertainties is contained in Northrop Grumman’s Annual Report on Form 10-K and in our other filings with the Securities and Exchange Commission. They include:

• our dependence on the U.S. Government for a substantial portion of our business

• significant delays or reductions in appropriations for our programs and U.S. Government funding more broadly

• investigations, claims, disputes, enforcement actions and/or litigation

• the use of estimates when accounting for our contracts and the effect of contract cost growth and/or changes in estimated contract revenues and costs

• our exposure to additional risks as a result of our international business, including risks related to geopolitical and economic factors, laws and regulations

• the improper conduct of employees, agents, subcontractors, suppliers, business partners or joint ventures in which we participate and the impact on our reputation, our ability to do business, and our financial position, results of operations and/or cash flows

• cyber and other security threats or disruptions faced by us, our customers or our suppliers and other partners

• the performance and financial viability of our subcontractors and suppliers and the availability and pricing of raw materials and components

• changes in procurement and other laws, regulations and practices applicable to our industry, findings by the U.S. Government as to our compliance with such laws and regulations, and changes in our customers’ business practices globally

• increased competition within our markets and bid protests

• the ability to maintain a qualified workforce

• our ability to meet performance obligations under our contracts, including obligations that are technologically complex, require certain manufacturing expertise or are dependent on factors not wholly within our control

• environmental matters, including unforeseen environmental costs and government and third party claims

• natural and/or environmental disasters

• the adequacy and availability of our insurance coverage, customer indemnifications or other liability protections

• products and services we provide related to hazardous and high risk operations, which subject us to various environmental, regulatory, financial, reputational and other risks

• the future investment performance of plan assets, changes in actuarial assumptions associated with our pension and other post-retirement benefit plans and legislative or other regulatory actions impacting our pension, post-retirement and health and welfare plans

• our ability successfully to integrate the Orbital ATK business and realize fully the anticipated benefits of the acquisition, without adverse consequences

• our ability to exploit or protect intellectual property rights

• our ability to develop new products and technologies and maintain technologies, facilities, and equipment to win new competitions and meet the needs of our customers

• changes in business conditions that could impact business investments and/or recorded goodwill or the value of other long-lived assets

• unanticipated changes in our tax provisions or exposure to additional tax liabilities

Additional information regarding these risks and other important factors can be found in the section entitled “Risk Factors” in our 2017 Annual Report on Form 10-K and from time to time in our other filings with the SEC.

You are urged to consider the limitations on, and risks associated with, forward-looking statements and not unduly rely on the accuracy of forward-looking statements. These forward-looking statements speak only as of the date this release is first issued or, in the case of any document incorporated by reference, the date of that document. We undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by applicable law.

This release also contains non-GAAP financial measures. A definition and discussion of these non-GAAP financial measures are included in this release.