Exhibit 99.1

Mimecast Announces Fourth Quarter and Full Year 2018 Financial Results

Fourth Quarter Highlights

Lexington, MA – May 14, 2018 (GLOBE NEWSWIRE) Mimecast Limited (NASDAQ: MIME), a leading email and data security company, today announced financial results for the fourth quarter and full year ended March 31, 2018.

“I’m extremely pleased with how we performed in 2018.  We worked tirelessly to bolster our customers’ cyber resilience through the constant innovation of our platform and the introduction of new services like Sync and Recover” stated Peter Bauer, CEO of Mimecast.

Mimecast’s CFO Peter Campbell noted, “We are proud of our ability to consistently exceed expectations on revenue at the same time showing improvements in our bottom line as we progress to our long-term targets.”

Fourth Quarter 2018 Financial Highlights

Full Year 2018 Financial Highlights

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Reconciliations of the non-GAAP financial measures provided in this press release to their most directly comparable GAAP financial measures are provided in the financial tables included at the end of this press release. An explanation of these measures and how they are calculated is also included under the heading “Non-GAAP Financial Measures.”

Business Highlights

Business Outlook

Mimecast is providing guidance for the first quarter and fiscal year 2019.

First Quarter 2019 Guidance:

For the first quarter of 2019, constant currency revenue growth is expected to be in the range of 26% to 28% and revenue is expected to be in the range of $76.3 million to $77.1 million. Our guidance is based on exchange rates as of April 30, 2018 and includes an estimated positive impact of $2.8 million resulting from the weakening of the U.S. dollar compared to the prior year. Adjusted EBITDA for the first quarter is expected to be in the range of $9.0 million to $10.0 million.  

Fiscal Year 2019 Guidance:

For the full year 2019, revenue is expected to be in the range of $327.0 million to $338.0 million or 23% to 27% revenue growth in constant currency.  Foreign exchange rate fluctuations are positively impacting this guidance by an estimated $6.3 million. Adjusted EBITDA is expected to be in the range of $49.0 million to $51.0 million.

GAAP net loss is the most comparable GAAP measure to Adjusted EBITDA. Adjusted EBITDA differs from GAAP net loss in that it excludes depreciation, amortization, disposals and impairments of long-lived assets, share-based compensation expense, restructuring expense, interest income and interest expense, the provision for income taxes and foreign exchange (expense) income and includes rent paid in the period related to locations which are accounted for as build-to-suit facilities. Mimecast is unable to predict with reasonable certainty the ultimate outcome of these exclusions without unreasonable effort. Therefore, Mimecast has not provided guidance for GAAP net loss or a reconciliation of forward-looking Adjusted EBITDA guidance to GAAP net loss.

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Conference Call and Webcast Information

Mimecast will host a conference call to discuss these financial results for investors and analysts at 4:30 pm EDT (UTC-05:00) on May 14, 2018. To access the conference call, dial (844) 815-2878 for the U.S. and Canada and (615) 800-6885 for international callers and enter conference ID# 1159538.  The call will also be webcast live on the investor relations section of the Company’s website http://investors.mimecast.com.  An audio replay of the call will be available two hours after the live call ends by dialing (855) 859-2056 for U.S. and Canada or (404) 537-3406 for international callers, and entering passcode ID# 1159538.  In addition, an archive of the webcast will be available on the investor relations section of the company’s website http://investors.mimecast.com.

About Mimecast Limited

Mimecast Limited (NASDAQ: MIME) makes business email and data safer for more than 30,400 customers and millions of employees worldwide. Founded in 2003, the Company’s next-generation cloud-based security, archiving and continuity services protect email, and deliver comprehensive email risk management in a single, fully-integrated subscription service. Mimecast reduces email risk and the complexity and cost of managing the array of point solutions traditionally used to protect email and its data. For customers that have migrated to cloud services like Microsoft^® Office 365™, Mimecast mitigates single vendor exposure by strengthening security coverage, combating downtime and improving archiving.

Mimecast and the Mimecast logo are registered trademarks of Mimecast. All other third party trademarks and logos contained in this press release are the property of their respective owners.

Non-GAAP Financial Measures

We have provided in this press release financial information that has not been prepared in accordance with GAAP. We use these non-GAAP financial measures internally in analyzing our financial results and believe they are useful to investors, as a supplement to GAAP measures, in evaluating our ongoing operational performance. We believe that the use of these non-GAAP financial measures provides an additional tool for investors to use in evaluating ongoing operating results and trends and in comparing our financial results with other companies in our industry, many of which present similar non-GAAP financial measures to investors.

Non-GAAP financial measures should not be considered in isolation from, or as a substitute for, financial information prepared in accordance with GAAP. Investors are encouraged to review the reconciliation of these non-GAAP financial measures to their most directly comparable GAAP financial measures provided in the financial statement tables included below in this press release.

Revenue Constant Currency Growth Rate. We believe revenue constant currency growth rate is a key indicator of our operating results. We calculate revenue constant currency growth rate by translating revenue from entities reporting in foreign currencies into U.S. dollars using the comparable foreign currency exchange rates from the prior fiscal period. To determine projected revenue growth rates on a constant currency basis for the first quarter and full year 2019, expected revenue from entities reporting in foreign currencies will be translated into U.S. dollars using the comparable prior year period’s monthly average foreign currency exchange rates.

Adjusted EBITDA and Adjusted EBITDA margin. We believe that Adjusted EBITDA and Adjusted EBITDA margin are key indicators of our operating results. We define Adjusted EBITDA as net loss, adjusted to exclude: depreciation, amortization, disposals and impairments of long-lived assets, share-based compensation expense, restructuring expense, interest income and interest expense, the provision for income taxes and foreign exchange (expense) income predominantly related to the elimination of intercompany balances and includes rent paid in the period related to locations which are accounted for as build-to-suit facilities. We define Adjusted EBITDA margin as Adjusted EBITDA over revenue in the period.

Non-GAAP net (loss) income. We define non-GAAP net (loss) income as net loss less share-based compensation expense, amortization of acquired intangible assets, impairment of long-lived assets, restructuring expenses and the income tax effect of non-GAAP adjustments. We consider this non-GAAP financial measure to be a useful metric for management and investors because it excludes the effect of share-based compensation expense, certain other “one-time” charges and related income tax effects so that our management and investors can compare our recurring core business net results over multiple periods. There are a number of limitations related to the use of non-GAAP net (loss) income versus net loss calculated in accordance with GAAP. For example, as noted above, non-GAAP net (loss) income excludes share-based compensation expense, certain other “one-time” charges and related income tax effects. In addition, the components of the costs that we exclude in our calculation of non-GAAP net (loss) income may differ from the components that our peer companies exclude when they report their non-GAAP results of operations. Management compensates for these limitations by providing specific information regarding the GAAP amounts excluded from non-GAAP net (loss) income and evaluating non-GAAP net (loss) income together with net loss calculated in accordance with GAAP.

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Free cash flow. We define free cash flow as net cash provided by operating activities minus capital expenditures. We consider free cash flow to be a liquidity measure that provides useful information to management and investors about the amount of cash generated by the business that, after the acquisition of property, equipment and capitalized software, can be used for strategic opportunities, including investing in our business, and strengthening the balance sheet. Analysis of free cash flow facilitates management’s comparisons of our operating results to competitors’ operating results. A limitation of using free cash flow versus the GAAP measure of net cash provided by operating activities as a means for evaluating our company is that free cash flow does not represent the total increase or decrease in the cash balance from operations for the period because it excludes cash used for capital expenditures during the period. Management compensates for this limitation by providing information about our capital expenditures on the face of the cash flow statement and in the liquidity and capital resources discussion included in our annual and quarterly reports filed with the Securities and Exchange Commission.

Safe Harbor for Forward-Looking Statements

Statements in this press release regarding management’s future expectations, beliefs, intentions, goals, strategies, plans or prospects, including, without limitation, the statements relating to our progress on achieving long-term financial targets, the future success of new products and services, and Mimecast’s future financial performance on both a GAAP and non-GAAP basis under the heading “Business Outlook” above, may constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and other federal securities laws. All statements, other than statements of historical fact, are statements that could be deemed forward-looking statements, including statements containing the words “predicts,” “plan,” “expects,” “anticipates,” “believes,” “goal,” “target,” “estimate,” “potential,” “may,” “might,” “could,” “see,” “seek,” “forecast,” and similar words. Mimecast intends all such forward-looking statements to be covered by the safe harbor provisions for forward-looking statements contained in Section 21E of the Exchange Act and the Private Securities Litigation Reform Act of 1995. Such forward-looking statements involve known and unknown risks, uncertainties and other factors including those risks, uncertainties and factors detailed in Mimecast’s filings with the Securities and Exchange Commission. As a result of such risks, uncertainties and factors, Mimecast’s actual results may differ materially from any future results, performance or achievements discussed in or implied by the forward-looking statements contained herein. Mimecast is providing the information in this press release as of this date and assumes no obligations to update the information included in this press release or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

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MIMECAST LIMITED

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(in thousands, except per share amounts)

(unaudited)

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MIMECAST LIMITED

CONDENSED CONSOLIDATED BALANCE SHEETS

(in thousands, except share and per share amounts)

(unaudited)

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MIMECAST LIMITED

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(in thousands)

(unaudited)

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Key Performance Indicators

In addition to traditional financial metrics, such as revenue and revenue growth trends, we monitor several other non-GAAP financial measures and non-financial metrics to help us evaluate growth trends, establish budgets, measure the effectiveness of our sales and marketing efforts and assess operational efficiencies. The key performance indicators that we monitor are as follows:

Reconciliation of Non-GAAP Financial Measures

The following table presents a reconciliation of revenue growth rate, as reported to revenue constant currency growth rate:

The following table presents a reconciliation of net loss to Adjusted EBITDA:

(1) The impairments of long-lived assets and the restructuring expense during the three months and year ended March 31, 2018 related to the exit from our former North American headquarters facility located in Watertown, Massachusetts.

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The following table presents a reconciliation of Net loss to Non-GAAP net (loss) income (in thousands, except per share amounts):

(1) Prior period amounts have been updated to conform to the current period presentation.

(2) The impairments of long-lived assets and the restructuring expense during the three months and year ended March 31, 2018 related to the exit from our former North American headquarters facility located in Watertown, Massachusetts.

The following table presents a reconciliation of Net cash provided by operating activities to Free Cash Flow (in thousands):

Share-based compensation expense for the three and twelve months ended March 31, 2018 and 2017 (in thousands):

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Revenue Constant Currency Growth Rate reconciliation (dollars in millions):

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Mimecast Social Media Resources

Press Contact

Alison Raymond Walsh
Press@Mimecast.com
617-393-7126

Investor Contact

Robert Sanders

Investors@Mimecast.com

617-393-7074

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