The board of directors of Proto Labs, Inc. is soliciting proxies for use at the Annual Meeting to be held on May 19, 2020,18, 2022, and at any adjournment or postponement of the meeting.

The following table sets forth information as of March 24, 202023, 2022 regarding the beneficial ownership of our common stock by:

The percentage of beneficial ownership is based on 26,675,19227,488,413 shares of common stock outstanding as of March 24, 2020.23, 2022. Except as disclosed in the footnotes to this table and subject to applicable community property laws, we believe that each shareholder identified in the table possesses sole voting and investment power over all shares of common stock shown as beneficially owned by the shareholder. Unless otherwise indicated in the table or footnotes below, the address for each beneficial owner is c/o Proto Labs, Inc., 5540 Pioneer Creek Drive, Maple Plain, Minnesota 55359.

Sven WehrweinArchie Black leads our board of directors in his role as Chairman. Our board of directors believes that its leadership structure is the appropriate one for our companyCompany in light of the importance of maintaining independent board leadership and engagement.

Our management is responsible for defining the various risks facing our company,Company, formulating risk management policies and procedures, and managing our risk exposures on a day-to-day basis. The board’s responsibility is to monitor our risk management processes by using board meetings, management presentations and other opportunities to educate itself concerning our material risks and evaluating whether management has reasonable controls in place to address the material risks; the board is not responsible, however, for defining or managing our various risks. The full board is responsible for monitoring management’s responsibility in the area of risk oversight. In addition, the audit committee and compensation committee have risk oversight responsibilities in their respective areas of focus, on which they report to the full board. Management reports from time to time to the full board, audit committee and compensation committee on risk management. The board focuses on the material risks facing our company,Company, including operational, credit, liquidity, legal and cybersecurity risks, to assess whether management has reasonable controls in place to address these risks.

In consultation with other members of the board of directors, the nominating and governance committee is responsible for identifying individuals who it considers qualified to become board members. The nominating and governance committee will screen potential director candidates, including those recommended by shareholders, and recommend to the board of directors suitable nominees for the election to the board of directors. The nominating and governance committee uses a variety of methods for identifying and evaluating nominees for directors. The nominating and governance committee regularly assesses the appropriate size and composition of the board of directors, the needs of the board of directors and the respective committees of the board of directors, and the qualifications of candidates in light of these needs. Candidates may come to the attention of the nominating and governance committee through shareholders, management, current members of the board of directors, or search firms. The evaluation of these candidates may be based solely upon information provided to the committee or may include discussions with persons familiar with the candidate, an interview of the candidate or other actions the committee deems appropriate, including the use of third parties to review candidates.

In considering whether to recommend an individual for election to the board, the nominating and governance committee considers, as required by the corporate governance guidelines and its charter, the board’s overall balance of diversity of perspectives, backgrounds, and experiences, although it does not have a formal policy regarding the consideration of diversity of board members. The nominating and governance committee views diversity expansively and considers, among other things, breadth and depth of relevant business and board skills and experiences, educational background, employment experience and leadership performance as well as those intangible factors that it deems appropriate to develop a heterogeneous and cohesive board, such as integrity, achievements, judgment, intelligence, personal character, the interplay of the candidate’s relevant experience with the experience of other board members, the willingness of the candidate to devote sufficient time to board duties, and likelihood that he or she will be willing and able to serve on the board for an extended period of time.

The nominating and governance committee will consider a recommendation by a shareholder of a candidate for election as a Proto Labs director. Shareholders who wish to recommend individuals for consideration by the

nomination at our Annual Meeting of Shareholders the following year. Our by-laws provide that such notice should be received no less than 90 days prior to the first anniversary of the preceding year’s Annual Meeting, except in certain circumstances. All recommendations must contain the information required in our by-laws and corporate governance guidelines, including, among other things, the identification of the nominee, a written consent by the recommended individual to agree to be named in our proxy statement and to serve as director if elected, and the name and address of the shareholder submitting the nomination. Shareholders may also have the opportunity to include nominees in our proxy statement by complying with the requirements set forth in Section 2.17 of our by-laws. Recommendations must be received by the Secretary within the timeframes noted under “Submission of Shareholder Proposals and Nominations.”

Our by-laws include a “proxy access” provision for director nominations under which eligible shareholders may nominate candidates for election to our board and inclusion in our proxy statement. The “proxy access” provision permits an eligible shareholder, or an eligible group of up to 20 shareholders, owning continuously for at least three years shares of our companyCompany representing an aggregate of at least three percent of the voting power entitled to vote in the election of directors, to nominate and include in our annual meeting proxy materials director nominees not to exceed the greater of (i) two or (ii) 25 percent of the number of directors then serving on our board, or, if such amount is not a whole number, the closest whole number below 25 percent, but not less than two. Such nominations are subject to certain eligibility, procedural, and disclosure requirements set forth in section 2.17 of our by-laws, including the requirement that our companyCompany must receive notice of such nominations not less than 120 calendar days prior to the anniversary date of the prior year’s annual proxy materials mailing, except as otherwise provided in section 2.17 of our by-laws.

Our board of directors has reviewed the materiality of any relationship that each of our directors has with us, either directly or indirectly. Based on this review, our board has determined that, with the exception of Victoria M. Holt,Dr. Robert Bodor, our current Chief Executive Officer, all of the directors and director nominees are “independent directors” as defined by Section 303A.02 of the New York Stock Exchange Listed Company Manual.

We have adopted a code of ethics and business conduct relating to the conduct of our business by our employees, officers and directors, which is posted on our website at www.protolabs.com under the investor relations section. Annually, our employees are required to complete code of conduct and business ethics training. We plan to post to our website at the address described above any future amendments or waivers to our code of ethics and business conduct.

Under our Corporate Governance Guidelines, a process has been established by which shareholders and other interested parties may communicate with members of the board of directors. Any shareholder or other interested party who desires to communicate with the board, individually or as a group, may do so by writing to the intended member or members of the board, c/o Secretary, Proto Labs, Inc., 5540 Pioneer Creek Drive, Maple Plain, Minnesota 55359. A copy of our Corporate Governance Guidelines is available at www.protolabs.com under the investor relations section.

All communications received in accordance with these procedures will initially be received and processed by the office of our Secretary to determine that the communication is a message to one or more of our directors and will be relayed to the appropriate director or directors. The director or directors who receive any such communication will have discretion to determine whether the subject matter of the communication should be brought to the attention of the full board or one or more of its committees and whether any response to the person sending the communication is appropriate.

During 2019,2021, the full board of directors met four times in person and held one meetingsix meetings via teleconference. All fourvideoconference. Six of the in-person meetings were preceded and/or followed by an executive session of the independent directors, chaired by Mr. WehrweinBlack or the acting chair of the meeting. Each of our incumbentthen-serving directors attended at least 75% percent of the meetings of the board and any committee on which they served in 2019.2021. We do not maintain a formal policy regarding the board’s attendance at annual shareholder meetings; however, board members are

Our board of directors has established an audit committee, a compensation committee and a nominating and governance committee. The charters of these committees are posted on our website at www.protolabs.com under the investor relations section.

The current composition and responsibilities of each committee, as well as the number of times it met during 2019,2021, are described below.

Each of the members of our audit committee meets the requirements for independence and financial literacy under the applicable rules and regulations of the SEC and the NYSE. Our board of directors has determined that Sven A. Wehrwein is an audit committee financial expert, as defined under the applicable rules of the SEC. The audit committee met 10seven times in 2019.2021.

Each member of our nominating and governance committee satisfies the NYSE independence standards. The nominating and governance committee met threesix times in 2019.2021.

In addition, the compensation committee has the authority to select, retain and compensate compensation consulting firms and other experts as it deems necessary to carry out its responsibilities.

Each member of our compensation committee satisfies currentthe NYSE independence standards and is a “non-employee director” as that term is defined in Rule 16b-3 under the Securities Exchange Act of 1934. The compensation committee met eight times in 2019.2021.

Since the beginning of 2019,2021, we have engaged in the following transactions with certain of our executive officers, directors, holders of more than 5% of our voting securities andor their affiliates andor immediate family members:

During the year ended December 31, 2019,2021, we recognized revenue from our customer Rockwell Automation (“Rockwell”) in the approximate amount of $550,000.$140,000. Our sales to Rockwell were made on terms consistent with the terms we provide to our other customers. Mr. Chand is a director and memberchair of our compensation committee and nominating and governance committee and Senior Vice President and Chief Technology Officer of Rockwell. This arrangement did not exceed the NYSE’s threshold of 2% of Rockwell’s consolidated gross revenues.

Our board of directors has adopted a written statement of policy regarding transactions with related persons, which we refer to as our related person policy. Subject to the exceptions described below, our related person policy requires our audit committee to review and approve any proposed related person transaction and all material facts with respect thereto. In reviewing a transaction, our audit committee will consider all relevant facts and circumstances, including (1) whether the terms are fair to us, (2) whether the transaction is material to us, (3) the role the related person played in arranging the transaction, (4) the structure of the transaction, (5) the interests of all related persons in the transaction, and (6) whether the transaction has the potential to influence the exercise of business judgment by the related person or others. Our audit committee will not approve or ratify a related person transaction unless it determines that, upon consideration of all relevant information, the transaction is beneficial to us and our shareholders and the terms of the transaction are fair to us. No related person transaction will be consummated without the approval or ratification of our audit committee. Under our related person policy, a related person includes any of our directors, director nominees, executive officers, any beneficial owner of more than 5% of our common stock and any immediate family member of any of the foregoing. Related party transactions exempt from our policy include payment of compensation by us to a related person for the related person’s service to us as an employee, director or executive officer, transactions available to all of our employees and shareholders on the same terms and transactions between us and the related person that, when aggregated with the amount of all other transactions between us and the related person or its affiliates, involve $120,000 or less in a year.

Eight directors will be elected at the Annual Meeting. Upon the recommendation of the nominating and governance committee, the board of directors has nominated for election the eight persons named below. Each has consented to being named a nominee and will, if elected, serve until the next Annual Meeting of Shareholders or until a successor is duly elected. There are no family relationships between any director and any executive officer. Each nominee listed below is currently a director of Proto Labs and, with the exception of Ms. Greiner who joined the Board in November 2021, has been duly elected by the shareholders.

As set forth in our Third Amended and Restated Articles of Incorporation, as amended, each director shall be elected by the vote of the majority of the votes cast with respect to the director, provided that directors shall be elected by a plurality of the votes present and entitled to vote on the election of directors at any such meeting for which the number of nominees (other than nominees withdrawn on or prior to the day preceding the date we first mail our notice for such meeting to the shareholders) exceeds the number of directors to be elected. A majority of the votes cast means that the votes cast “for” a director nominee must exceed the votes that are voted “against” that director.

Compensation Table and the other tables, accompanying footnotes and narrative that follow in this section. This Compensation Discussion and Analysis explains our executive compensation philosophy, objectives and design, our compensation-setting process, our executive compensation program components and the decisions made in 20192021 affecting the compensation of our named executive officers. Throughout this section, we refer to the following individuals as our “named executive officers”:

This section provides an overview of our performance, key decisions and actions made by our compensation committee during the course of the year, a summary of the governance features of our executive compensation program, and a history of our say-on-pay results.

In 2019,Like many companies, Protolabs faced internal and external disruptions to our business in 2021. Throughout the Company made progress on a numberyear, we worked to overcome these challenges, and we achieved our strategic goals to enable us to drive future growth. Despite the obstacles of fronts; however a numberthe global pandemic and the resulting economic impacts over the past two years, our business strategy and market opportunity remain strong. 2021 was highlighted by two major accomplishments that transformed our business and position us for the future. First, we completed the largest acquisition in our history and joined forces with Hubs to expand our service capabilities with the intent of our financial measures were below targets. We remained focused on the execution of a number of key strategic initiatives, including but not limited to: (i) enhancingservicing more customer use cases. Second, we revamped our e-commerce experience and made significant enhancements to our internal systems architecture to improve our customer experience, achieve internal productivity improvement, improve the speed and scalability of new capabilities and acquisitions, and provide improved access to data for customer insights, (ii) the integration of RAPID Manufacturing Group, LLC (RAPID), which was acquired in November 2017, and (iii) the continued expansion of the envelope of parts that we can make for our customers across all our services. Our revenue increased by 2.9% in 2019 compared with 29.3% 2018 and our net cash provided by operating activities totaled $116.1 million in 2019. In addition, we continued to evolve our go-to-market models with the goal of delivering sustainable revenue growth over the long term.experience.

SinceAlthough our IPO in February 2012, we have delivered higher total shareholder returnsreturn (TSR) than companies in our compensationwas not as strong as peers at the end of 2021, it has been historically very strong, exceeding that of the peer group, the S&P 500 and the Russell 2000 Growth Index. OurIndex from our IPO through 2020. While our shareholder value has declined in 2021 relative to these measures, our board of directors and senior management team believe this is temporary and are strongly committed to maintaining our company’sCompany’s long-term sustainable growth.

Our compensation committee is committed to establishing an executive compensation program that reflects strong corporate governance attributes. The following table summarizes those corporate governance attributes.

The Compensation Committee values the opinions of our shareholders. At our 20192021 annual meeting, the say-on-paysay-on- pay proposal received the approval of approximately 97% of the shares voted on the proposal. Our compensation committeeWe considered this result to be an endorsement by our shareholders of our compensation program and maintained the majority of the fundamental features of our 20182020 program for 2019.2021. Further, since our companyCompany began holding the say-on-paysay-on- pay vote, our shareholders have been overwhelmingly supportive of our program,compensation programs, with our companyCompany receiving greater than 90% in each year.

We believe our success depends in large measure on our ability to attract, retain and motivate a talented senior management team to effectively lead our companyCompany in a dynamic and changing business environment, and that a competitive executive compensation program is essential to that effort. We believe that our executive compensation program should support our short- and long-term strategic and operational objectives, and reward corporate and individual performance that contributes to creating value for our shareholders.

Consistent with this philosophy, our executive compensation program incorporates the following key principles and objectives:

compensation committee regarding his or her own compensation. The compensation committee communicates its views and decisions regarding compensation arrangements for our executive officers to our CEO, who generally has been responsible for implementing the arrangements.

In determining executive compensation, our compensation committee reviews and considers a number of factors, including individual and corporate performance, input from our CEO, compensation market data from third party compensation surveys (including Pearl Meyer, our independent compensation consultant), our compensation philosophy and key principles, the pay practices of a set of comparable companies, feedback received from shareholders concerning say-on-pay, and the committee’s collective experience and knowledge. We have used market data primarily as a reference point to assess whether our compensation practices are reasonable, competitive and likely to achieve our objectives, and actually deliver compensation in amounts that are consistent with the compensation committee’s assessment of our company’sCompany’s relative performance. As part of these assessments, we assumed that target total compensation levels were likely to be reasonable and competitive if they approximated the market median we calculated from the surveys and other compensation data we utilized which for us generally meant a range between 85% and 115% of the market median. The utilization of a range is largely in recognition of the limitations of the survey data that include companies with limited degrees of comparability to our companyCompany and position titles that may encompass positions with responsibilities that differ to varying degrees from the responsibilities of a similarly titled position within our company.Company. As a result, we diddo not establish specific compensation amounts or parameters for any executive officer position based on market data, in 2018, recognizing that factors unique to each individual will ultimately determine that individual’s compensation, which may not necessarily be within the median range. Our compensation committee approves all awards to our executive officers under our 2012 Long-Term Incentive Plan, as amended to date (the “LTIP”).

Below is information about the companies in the peer group, as well as the corresponding information for Proto LabsProtolabs that Pearl Meyer referenced when constructing the peer group:

The compensation committee uses data about executive compensation at peer group companies as a tool to assess the reasonableness of the total compensation paid to our executive officers. As discussed above, we do not establish a percentile which any part of our executive’s compensation or any executive’s overall compensation must meet or exceed.

Our executive compensation program historically has been comprised of three primary elements—base salary, annual cash incentive, and equity-based long-term incentives. The primary elements of our compensation

program for 20192021 were consistent with our 20182020 compensation program. While all elements of our executive compensation program are intended to collectively achieve our overriding purpose of attracting, retaining and motivating talented executives, the table below identifies the additional specific purposes of each element as reflected in our 20192021 compensation program.

Salaries were temporarily reduced for a portion of 2020, and returned to normal levels by the end of that year. The annual base salary of each of our named executive officers was increased for 2019 compared to 2018 asis set forth in the table below as a result of merit-based increases based on such officer’s contributions to our company, our company’s overall success in 2019, and changes in the competitive market.below:

All of our named executive officers participate in our annual incentive program. The annual incentive program payouts were a function of two metrics:

Revenue growth and AOI were selected as the primary financial objectives for determining the 20192021 annual incentive payouts because our primary objective continues to be to grow our companyCompany profitably.

A target payout expressed as a percentage of annual base salary is established for each named executive officer annually. For 2019,2021, their target payout percentages were as follows:

The target payout percentages for each named executive officer remained unchanged from the 20182020 percentages in light of the compensation committee’s determination that the target percentages from 20182020 remained competitive.

The revenue factor of our plan pays out 100% at targeted revenue achievement on a consolidated basis or for each region, as applicable, for each named executive officer. The payout is zero for 20192021 revenue below specifiedthe threshold amountsof 86% attainment of the annual targets for our companyCompany as a whole and each of its business units,units. The payment is 30% of the annual bonus at thosethe threshold amounts of 90% attainment, and increases in amounts specified by the compensation committee to the degree revenue exceeds the respective threshold amounts up to a maximum of 200%.

The AOI factor is 100% at targeted AOI on a consolidated basis for each named executive officer. For the AOI factor, the payout is zero for 20192021. AOI below a specified threshold amount for our companyCompany as a whole, is 40% at the threshold amount, and increases in amounts specified by the compensation committee to the degree that AOI exceeds the threshold amount up to a maximum of 200%. For AOI performance between threshold and target, the payout factor would increase proportionately between 40% and 100%, or about 0.2 percentage points for each basis point in additional AOI, and between target and maximum, the payout factor would increase proportionately between 100% and 200%, or about 0.2 percentage points for each basis point in additional AOI.