Inogen Announces Fourth Quarter and Full Year 2016 Financial Results and Updates 2017 Guidance - Q4 2016 Sales Revenue up 47.2% Over the Same Period in 2015 - - Q4 2016 Net Income up 36.3% Over the

Inogen Announces Fourth Quarter and Full Year 2016 Financial Results and Updates 2017 Guidance

- Q4 2016 Sales Revenue up 47.2% Over the Same Period in 2015 -

- Q4 2016 Net Income up 36.3% Over the Same Period in 2015 -

- Q4 2016 Adjusted Net Income up 85.0% Over the Same Period in 2015 -

- Record Revenue for Full Year 2016 -

- Raises 2017 Guidance-

Goleta, California, February 28, 2017 - Inogen, Inc. (NASDAQ: INGN), a medical technology company offering innovative respiratory products for use in the homecare setting, today reported financial results for the three-month and twelve-month periods ended December 31, 2016.

Fourth Quarter 2016 Highlights

Full Year 2016 Financial Highlights

"We've once again seen solid revenue growth led by continued strong adoption by home medical equipment providers turning to portable oxygen concentrators," said Chief Executive Officer Raymond Huggenberger. "We continue to demonstrate that we are not only providing the best in class portable oxygen concentrators to our patients, but also helping our business-to-business customers improve their cost basis in the face of a challenging reimbursement climate."

Fourth Quarter 2016 Financial Results

Total revenue for the three months ended December 31, 2016 rose 25.7% to $50.9 million from $40.4 million in the same period in 2015. Domestic business-to-business sales exceeded expectations and grew 69.0% over the same period in 2015, primarily driven by traditional home medical equipment provider purchases and the continued strength of our private label partner. International business-to-business sales in the fourth quarter of 2016 also exceeded expectations, growing 42.2% over the comparative period in 2015, primarily due to success with our large partners in Europe and the addition of a new customer in South Korea. Direct-to-consumer sales rose 34.2% over the same period in 2015, approximately in line with expectations. Rental revenue decreased 28.3% from the same period in 2015, primarily due to the declines in Medicare rental reimbursement rates, continued declines in private-payor rates due to the lower Medicare rates, and a continued focus on sales versus rentals, partially offset by the one-time benefit of $2.0 million associated with the 21st Century Cures Act, which is expected to be non-recurring and retroactively increased the reimbursement rates in certain Medicare regions for the second half of 2016. Rental revenue declined to 16.2% of total revenue in the fourth quarter of 2016 from 28.4% of total revenue in the fourth quarter of 2015.

Gross margin was 48.5% in the fourth quarter of 2016 versus 49.5% in the comparative period in 2015. Sales gross margin was 49.9% in the fourth quarter of 2016 versus 48.0% in the fourth quarter of 2015. Sales gross margin improved primarily due to lower cost of goods sold per unit associated with the upgraded Inogen One G3 and the Inogen One G4, partially offset by an increase in sales mix toward lower margin business-to-business sales as volumes in these channels increased worldwide. Rental gross margin was 41.4% in the fourth quarter of 2016 versus 53.4% in the fourth quarter of 2015, primarily due to lower net revenue per rental patient as a result of reimbursement rate reductions, partially offset by the non-recurring $2.0 million benefit from the 21st Century Cures Act and lower cost of rental revenues associated with lower depreciation and servicing costs per patient.

Total operating expense increased to $18.5 million in the fourth quarter of 2016 versus $16.6 million in the fourth quarter of 2015 as the Company continued to make strategic investments in additional personnel and incurred increased patent defense legal costs. Total operating expense as a percentage of revenue decreased to 36.4% in the fourth quarter of 2016 from 41.0% in the fourth quarter of 2015.

Operating expense included research and development expense of $1.2 million in the fourth quarter of 2016, which was consistent with $1.2 million in the comparative period in 2015. Sales and marketing expense was $9.3 million in the fourth quarter of 2016 versus $8.7 million in the comparative period in 2015, primarily due to increased media expense and salesforce additions. General and administrative expense was $8.0 million in the fourth quarter of 2016 versus $6.6 million in the comparative period in 2015, primarily due to increased personnel-related expenses and patent defense legal costs.

During the fourth quarter of 2016, the Company elected to early adopt Accounting Standards Update (ASU) 2016-09 ahead of the mandatory 2017 effective date for all U.S. public

companies. On March 30, 2016, the Financial Accounting Standards Board issued ASU 2016-09, Improvements to Employee Share-Based Payment Accounting, which simplifies the accounting for share-based payment transactions, including the income tax consequences. The impact of the adoption is favorable for full year 2016 and is expected to be favorable for 2017. The adoption led to a decrease in provision for income taxes of $6.0 million in full year 2016 (see accompanying table for recast of the prior quarters net income and related earnings per share).

Net income for the fourth quarter of 2016 increased 36.3% to $5.3 million from $3.9 million in the fourth quarter of 2015, or $0.25 per diluted common share compared to $0.19 in the fourth quarter of 2015. In the fourth quarter of 2016, Inogen's effective tax rate was 9.8% compared to negative 16.3% in the fourth quarter of 2015. Excluding the $1.7 million decrease in provision for income taxes associated with the adoption of ASU 2016-09, Inogen's fourth quarter 2016 effective tax rate would have been 39.7%. In the fourth quarter of 2015, Inogen's effective tax rate of negative 16.3% was primarily due to the tax benefit adjustments of $1.0 million, which were mainly related to a decrease in the valuation allowance related to California net operating losses. In addition, the effective tax rate in the fourth quarter of 2015 was impacted by an increase in equity compensation deductions and benefits associated with the federal research and development tax credit and the timing of stock dispositions in the fourth quarter of 2015.

Adjusted net income in the fourth quarter of 2016 increased 85.0% to $5.3 million from $2.8 million in the fourth quarter of 2015. Adjusted net income in the fourth quarter of 2016 did not include any non-recurring tax benefit adjustments, compared to $1.0 million of tax benefit adjustments in the fourth quarter of 2015 but it did include a $1.7 million reduction in provision for income taxes associated with ASU 2016-09.

Adjusted EBITDA for the three months ended December 31, 2016 rose 34.4% to $10.9 million from $8.1 million in the fourth quarter of 2015.

Cash, cash equivalents, and marketable securities were $113.9 million as of December 31, 2016, compared to $108.3 million as of September 30, 2016, an increase of $5.5 million in the fourth quarter of 2016. This compares to $82.9 million of cash, cash equivalents, and marketable securities as of December 31, 2015, an increase of $31.0 million in full year 2016.

Financial Outlook for 2017

Inogen is increasing its 2017 revenue guidance to a range of $233 to $239 million, which represents year-over-year growth of 14.9% to 17.8%. This compares to the previous revenue expectation of $230 to $236 million. The Company expects direct-to-consumer sales to be its fastest growing channel, followed by domestic business-to-business sales to be its second fastest growing channel, and international business-to-business sales to be its third fastest growing channel, where the strategy will continue to be heavily focused on the European markets. Inogen expects rental revenue to continue to decline in 2017 compared to 2016 based on lower average rental revenue per patient primarily due to the known cuts from Medicare competitive bidding, continued reductions of private insurance and Medicaid rates, and a continued focus on sales versus rentals.

Inogen is also increasing its full year 2017 net income and Adjusted net income guidance to $21 to $23 million, representing 2.3% to 12.1% year-over-year growth. This compares to the previous guidance range of $16 to $18 million. Inogen estimates that the adoption of ASU 2016-09 will lead to a decrease in provision for income taxes of approximately $5.0 million in 2017

based on forecasted stock activity, which will lower our effective tax rate. Excluding the $5.0 million decrease in provision for income taxes expected in 2017, the Company expects an effective tax rate of approximately 37%. After giving effect to ASU 2016-09, the Company expects an effective tax rate including stock compensation deductions to vary quarter to quarter depending on the amount of pre-tax net income and on the timing and size of stock option exercises.

Inogen is also increasing its guidance range for full year 2017 Adjusted EBITDA to $46 to $50 million, representing 6.0% to 15.2% year-over-year growth. This compares to the previous guidance range of $45 to $49 million.

Inogen continues to expect net positive cash flow for 2017 with no additional equity capital required to meet its current operating plan.

Individuals interested in listening to the conference call today at 1:30pm PT/4:30pm ET may do so by dialing (855) 427-4393 for domestic callers or (484) 756-4258 for international callers. Please reference Conference ID: 59665587. To listen to a live webcast, please visit the Investor Relations section of Inogen's website at: http://investor.inogen.com/.

A replay of the call will be available beginning February 28, 2017 at 4:30pm PT/7:30pm ET through 4:30pm PT/7:30pm ET on March 1, 2017. To access the replay, dial (855) 859-2056 or (404) 537-3406 and reference Conference ID: 59665587. The webcast will also be available on Inogen's website for one year following the completion of the call.

Inogen has used, and intends to continue to use, its Investor Relations website, http://investor.inogen.com/, as a means of disclosing material non-public information and for complying with its disclosure obligations under Regulation FD. For more information, visit http://investor.inogen.com/.

Inogen is innovation in oxygen therapy. We are a medical technology company that develops, manufactures and markets innovative oxygen concentrators used to deliver supplemental long-term oxygen therapy to patients suffering from chronic respiratory conditions.

For more information, please visit www.inogen.com.

Cautionary Note Concerning Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, including, among others, statements regarding anticipated growth opportunities; expectations that rental revenue will continue to decline due to reductions in Medicare and private payor reimbursement rates; expectations of growth in the direct-to-consumer, business-to-business and international sales channels; the expected impact of ASU 2016-09; and financial guidance for 2017, including revenue, net income, Adjusted EBITDA, Adjusted net income , net cash flow, effective tax rates and tax benefit adjustments, and the need for equity financing. Forward-looking statements are subject to numerous risks and uncertainties that could cause actual results to differ materially from currently anticipated results, including but not limited to, risks arising from the possibility that Inogen will not realize anticipated revenue; the impact of reduced reimbursement rates, including private payor reductions and reductions in connection with competitive bidding and the Center for Medicare

and Medicaid Services (CMS) rules; the possible loss of key employees, customers, or suppliers; and intellectual property risks if Inogen is unable to secure and maintain patent or other intellectual property protection for the intellectual property used in its products. In addition, Inogen's business is subject to numerous additional risks and uncertainties, including, among others, risks relating to market acceptance of its products; its ability to continue its Inogen One G4 product rollout; competition; its sales, marketing and distribution capabilities; its planned sales, marketing, and research and development activities; interruptions or delays in the supply of components or materials for, or manufacturing of, its products; seasonal variations; unanticipated increases in costs or expenses; and risks associated with international operations. Information on these and additional risks, uncertainties, and other information affecting Inogen's business operating results are contained in Inogen's Quarterly Report on Form 10-Q for the quarter ended September 30, 2016, and in its other filings with the Securities and Exchange Commission. Additional information will also be set forth in Inogen's Annual Report on Form 10-K for the year ended December 31, 2016 to be filed with the Securities and Exchange Commission. These forward-looking statements speak only as of the date hereof. Inogen disclaims any obligation to update these forward-looking statements except as may be required by law.

Use of Non-GAAP Financial Measures

Inogen has presented certain financial information in accordance with U.S. GAAP and also on a non-GAAP basis for the three and twelve months ended December 31, 2016 and December 31, 2015. Management believes that non-GAAP financial measures, taken in conjunction with U.S. GAAP financial measures, provide useful information for both management and investors by excluding certain non-cash and other expenses that are not indicative of Inogen's core operating results. Management uses non-GAAP measures to compare Inogen's performance relative to forecasts and strategic plans, to benchmark Inogen's performance externally against competitors, and for certain compensation decisions. Non-GAAP information is not prepared under a comprehensive set of accounting rules and should only be used to supplement an understanding of Inogen's operating results as reported under U.S. GAAP. Inogen encourages investors to carefully consider its results under U.S. GAAP, as well as its supplemental non-GAAP information and the reconciliation between these presentations, to more fully understand its business. Reconciliations between U.S. GAAP and non-GAAP results are presented in the accompanying table of this release. For future periods, Inogen is unable to provide a reconciliation of non-GAAP measures without unreasonable effort as a result of the uncertainty regarding, and the potential variability of, the amounts of interest income, interest expense, depreciation and amortization, stock-based compensation, provisions for income taxes, and certain other infrequently occurring items, such as acquisition related costs, that may be incurred in the future.

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-- Financial Tables Follow --

(1) Reconciliations of net income attributable to common stockholders basic and diluted can be found in Inogen's Annual Report on Form 10-K to be filed.

1 Includes expenses associated with our 2015 audit committee investigation and related securities class action lawsuit that was subsequently dismissed on June 29, 2015.

2 Consists of a patent litigation settlement benefit partially offset by a litigation expense associated with a labor law class-action lawsuit that was accrued in the first quarter of 2016 and paid in the fourth quarter of 2016.

3 Tax benefit adjustments related to the release and adjustment of the valuation allowances associated with the net operating loss carryforwards for the quarter ended and for the year ended December 31, 2015.

Recast of the prior quarters net income and related earnings per share