Filed by GigCapital3, Inc.

Pursuant to Rule 425 under the Securities Act of 1933

Commission File No.: 001-39283

Subject Company: Lightning Systems, Inc.

The World’s Most Comprehensive Private-to-Public Equity (PPE)™ Business Initiative COMPANY OVERVIEW

Page 2 | GigCapital Company Overview Seeking Excellence GigCapital Global is a serial SPAC issuer and the first Private-to-Public Equity (PPE)™ business dedicated and to taking technology late-stage, executive high group quality private market. TMT GigCapital companies Global to the is a public pioneer as Our it launched “IPO-in-a-box” its first methodology SPAC in 2017. provides traditional an IPO alternative process, to and the our lengthy Mentor-Investors™ foster growth to the unicorn stage and beyond. Technology Strong SPAC Momentum SPACs with Statistics Limited Industry Overview Overlap the Because SPAC of process its effectiveness has gained in significant bringing interest companies from public, the fi- u More than $83 billion raised for 248 SPACs in 2020, an exceptional year for SPACs number nancial community of SPAC offerings. as evidenced SPACs by have the grown recent significantly growth in the in the last 10 years and exploded in 2020 to become a strong u 221 SPACs seeking acquisitions, 64 in the alternative path to liquidity, offering significant advantages TMT sector, at the beginning of 2021 such as shorter process duration, an ability to provide forward-looking financial projections, and immediate invest- u Trend in 2020 to have larger PIPEs including in ment analyst attention. excess of amount in the trust account Amount Raised from SPACs u Alternatives to PIPEs, such as convertible Seeking Acquisitions notes, used for funding of targets 21% 1% 2% 16% 6% SPAC Status by Year 7% 4% 2016 92% 8% 33% 7% 201 85% 3%3% 9% TECHNOLOGY 2% $22,525 2% 201 86% 12% 2% 201 32% 39% 28% 2% ($MM) CANNABIS ENERGY ESG FC&R FINANCIALS HEALTHCARE 2020 3%13% 88% 85% $476 $1,303 $3,859 $4,818 $3,025 $4,483 INDUSTRIALS REAL ESTATE TECHNOLOGY DIVERSIFIED NO TARGET Completed Announced Seeking iquidated $1,610 $1,280 $22,525 $10,665 $13,943 Sources: SPAC Market Snapshot, SPAC BMO Research Capital Newsletter, Markets, Dec. Jan. 21, 4, 2020 2021

GigCapital Company Overview | Page 3 Global Megatrends and Implications The are shaping global megatrends, our collective the future, macroeconomic include urbanization, and geostrategic environmental forces that changes, and deep. digitalization, Business and and enterprises globalization. must be Their keenly implications aware of are them broad and be part the tremendous of the solutions opportunities, to address but them, also to bestow not only benefits be able on to the benefit world from that we are citizens of, in order to attain long term prosperity. Accelerating Urbanization Calls for Smart and Sustainable Infrastructure 2050. Urban Based population on United is expected Nations data, to increase overall from growth today’s of the 53% world’s to 70% pop- by ulation will add close to 2.5 billion people to urban areas by 2050(1). The number countries, of new requiring mega-cities massive will increase investments rapidly, in smart particularly and sustainable in developing city infrastructures. the ongoing These demographic trends will be shift further and emphasized new population and challenged age structure. by Sustainability and Environment Underpin Long Term Growth Climate of the world’s change greatest and consequent concerns. environmental The United Nations and social Sustainable impacts Development are some Goals and the Paris Climate Agreement are driving the agenda and world’s efforts toward a green economy and sustainable solutions(2). Consumer sensitivity representing to sustainable-marketed today more than 50% products of total Consumer grew substantially Packaged in Goods the last (CPG) 5 years, market growth(3). Capital allocation in funds embracing Environmental, Social and Governance principles reached record numbers in the last few years(4). Digitalization Driving Massive Value and Changing Business Models Data the has cloud-based become enterprises’ platforms and most enabled valuable with asset. new Digital technologies transformation, including built AI, IoT, on drive mobile massive and robotics, business offer transformations companies across and new all industries business models, new opportunities with the scal- to ability, flexibility, turn, agility, are powering dynamism the heretofore movements infeasible. to address These the transformations, other megatrends. in Globalization Demand Global Perspectives and Execution in The Asia focus Pacific of the and global Latin growth America, has are been starting shifting. to bring Developing their economies countries, to particularly the forefront markets are of interlinked not only transitioning global trade to and more investments consumption-oriented flows. The emerging economies, are but prepared also starting and to able export to adapt capitals and and capitalize innovations. on the Enterprises evolving global that competitive landscape will be the winner of the 21st century. Sources: (2) (1) Report UN Framework of the UN Convention Economist on Network Climate for Change-FCC/CP/2-15/L. the UN 75th Anniversary- 9/Rev1 Sept. 2020 (4) (3) Blackrock New York University, – Sustainability: Stern The School tectonic of Business; shift transforming investing, Feb.2020.

Page 4 | GigCapital Company Overview GigCapital Mentor-Investor TMT PPE From Launch to Combination and Beyond GigCapital uity (PPE) is Global’s an expanded Mentor-Investor process designed with Private-to-Public for the industries Eq- a engaging SPAC, through with a prospective searching for target a business with a Letter-of-Intent combination target, (LOI) Acquisition with a technology Company focus, (SPAC) structured vehicle, as on regulated the Special by Purpose the SEC. and ness executing combination, a Definitive and mentoring Agreement the combined (DA), closing entity the to busi- exe-The entire process covers from the inception and the IPO of cute as a successful public growth company. P ASE P ASE 1 P ASE 2 P ASE 3 P ASE 4 Growth Inception Searching Engagement Closing & Exit phase 1: Inception | 2-3 MONTHS phase 3: Engagement | 1-3 MONTHS The Inception phase starts with forming the PPE™ execution Upon mutual interest with the potential combination target tors, team and of TMT launching experts, the entrepreneurs, Sponsorship LLC and team executive comprised opera- of by company, 4-6 weeks a LOI period is nominally to complete executed the due-diligence in 2-4 weeks, and followed exe- TMT and investment wealthy individuals, bankers. family offices, institutional investors, cute Agreement. a definitive GigCapital and mutually Global binding and its ecosystem Business Combination of partners have consistently demonstrated expedient Engagement phase IPO In addition book with to the balanced SEC filings, fundamental a key activity equity is that and of fixed creating income an execution across many transactions. investors. effective, the Upon Inception the declaration phase completes by the SEC with of the the S-1 being 3-6 MONTHS and start of trading on the stock exchange. IPO pricing Phase 4: Closing | GigCapital soned TMT Global’s investors, “IPO underwriters, in a Box” process research encompasses analysts, audi- sea-phase 2: Searching | 6-12 MONTHS tors, that of counsels, the completion IR, PR and of GAAP/PCAOB HR firms. The key audit gating and the factors filing are of In this phase, the PPE™ execution team screens thousands of TMT companies around the world and across diversified ver- an S-4 and becoming effective. technology-oriented ticals, meet with the owners entrepreneurial of financially leadership viable teams and pub- and To successfully close the combination, the PPE™ execution team secures the necessary financing, including the back-lic-listing-ready companies. stopping lenders and TMT equity fundamental investors, Subjects including financing avenues, rollover with public cur- maintaining as well as ensures the market-cap, the minimum providing listing conditions, the required including float rency, and strategic growth planning are key parts of the discussions with a potential target company’s leadership and owners. through minimum forward round-lot purchase shareholders. agreements, and securing the Phase 5: Growth & Exit | 2-5 YEARS participate Post-combination, actively selected at the newly members public of company’s GigCapital BOD Global and strategy, Strategic governance/compliance, Advisory Board, providing and continuous M&A advisory/guid- financing, ance for consolidation and growth.

GigCapital Company Overview | Page 5 Data-Driven Target Identification & Efficient Engagements 1: Investment Criteria 3: Demonstrated Execution • Seek technology leading with growth our deep categories domain in expertise sectors enabled by • quality Speed and partners certainty of execution is essential to attract • Identify or foreign the listed best companies available US in private those sectors and overseas private • Extensive tional personal M&A contacts and public and company respect in experience, the community with excep- • Seek leverage entrepreneurial public market owners for growth, / leadership rather than looking liquidity to • Proven market operational experience for track the record public and market extensive strategy capital as an exit 4: Post Combination 2: Superior Sourcing • Mentor-Investor™: identify, mentor, and recruit world-class • Leverage the GigCapital Global pipeline talent and align incentives • like Management Kaleyra, UpHealth reference or from Lightning previously eMotors announced deals, • Participation in the BOD of public company (governance, law firm, auditor, etc.) • Strong international capabilities and global experience • Financing for SPAC overhang cleanup & growths • Focus through on public partners combination looking to and move roll-up, to the and next not level cash out • M&A opportunity identification and geographic market expansion Egagemet Tracig PUBLIC DATA Targets & ~: 1 Outreach Quali?cation Mutual Interests O I Due Diligence DA deSPAC SOURCES Contacts DB ~10:1 ~2-3:1 ~4:1 O I Financials, Cap Table, Audit Status, Revenue, Exit Expectations, Pro?tability, etc. Comp Multiple, GigCapital Global, with over three years of SPAC operation, Ownership, has developed an infrastructure for capturing, screening, etc. and identifying high quality candidate targets, and an effi-gets cient of and interest. supportive This infrastructure process to engage supported and track screening the tar- of tinually ~5000 targets expanding in GigCapital2 a pipeline of and high GigCapital3, potential, mutually while con- in-portfolio terested targets companies. for future PPE platforms and M&A by the

A History of Success |CPaaS Kaleyra Becomes a Leading Global CPaaSGigCapital1 Case Study Kaleyra to Complete Acquisition of mGage Pro Forma Combined Revenue by Geography (1) After one year of joint work between the GigCapital and Kaleyra management teams, as part of GigCapital Mentor Investor™ methodology, Kaleyra signed a definitive agreement to acquire mGage, a global mobile engagement provider. The acquisition will expand existing US customer base and R&D footprint, network operator connections, with highly realizable cost synergies and cross-selling opportunities. Such combination results in Pro Forma Revenue of $361M, 26.5% Gross Margin and an EBITDA of $45M. mGage offers best of breed mobile engagement solution and Tier 1 connectivity, allowing enterprise clients to effectively engage with their customers through all mobile channels for a variety of use cases such as customer care, service alerts, multi[1]factor authentication and more. mGage is the perfect strategic fit, aligned with Kaleyra’s commitment to the investors at the combination with GigCapital1. Kaleyra + mGage Combination Highlights (2)

A History of Success |Digital Health GigCapital2 to Combine with UpHealth and Cloudbreak to Create a Unified and GigCapital2 PPE™ SPAC of $173M executed a fast-paced business combination agreement with UpHealth and Cloudbreak in Nov. 2020, with the plan of closing the combination in the 1st half of 2021. Comprising a total of six profitable and rapidly growing healthcare companies in digital and telehealth, digital pharmacy, and behavioral health, the combined company UpHealth Holdings, Inc. will list on the New York Stock Exchange under the ticker symbol “UPH”.The GigCapital2 team was thrilled to partner with the passion ate healthcare entrepreneurs of UpHealth and Cloudbreak, for our second transaction using the PPE platform methodology, where GigCapital Global will bring its management’s well-recognized and decades-long expertise to enable the successful transition of six late stage growth, complementary healthcare technology companies, to a unified, US public-market traded entity. Moving into the public arena will represent a major milestone to launch the unified UpHealth global ecosystem and fuel the next phase of explosive growth within the expanding Digital Health market. GigCapital2 Case Study Working with UpHealth and Cloudbreak for Successful Combination The entrepreneurial management teams that will make up UpHealth (itself the intended combination of 5 companies; some of which have already occurred) and Cloudbreak consistently delivered innovative technologies and services, global revenue growth and profitability as independent companies. As a unified public company, UpHealth Holdings will have a strong capital structure and great latitude to excel and achieve its projected accelerated financial growth by organic and strategic means. Members of GigCapital Global’s management will join UpHealth’s Board of Directors and Strategic Advisory Board, as per our Mentor Investor charter, and continue to provide audit, governance, business support, and work closely with UpHealth’s management team to integrate complementary products/services and accelerate business growth.

A History of Success |Reducing the Carbon Footprint Lightning eMotors to Merge with GigCapital3 to Lead the Class 3-7 Urban Commercial Zero Emission Vehicles (ZEV) Market GigCapital3 PPE™ SPAC of $200M is thrilled to partner with Lightning eMotors, where GigCapital3 brings its management’s well-recognized and decades-long technology public-market operational and entrepreneurial expertise to enable the successful transition of a high-growth EV company to a publicly traded entity. Lightning eMotors has successfully built out a proprietary, cost-efficient, scalable modular architecture, which is protected by robust IP that is far ahead of its competition. As a public company, Lightning eMotors will have a strong capital structure to invest in capacity expansion and additional technology development, both organically and through acquisitions, to become an international ZEV industry leader. The combination of Lightning eMotors and GigCapital3 will bring unique, attractive, and promising opportunities to all stockholders and stakeholders, while substantiating our commitment to support one of the highest impact megatrends of our lifetime: electrification of mobility solutions. GigCapital3 Case Study Innovative Financing for Lightning eMotors Amidst the frenzied pace of EV companies going public in 2020, GigCapital Global leadership orchestrated a first-of-its-kind financing package to ensure successful deSPAC, providing Lightning eMotors with a strong capital structure to execute its growth plan following the planned closed of the business combination. Members of the GigCapital Global team will join the Lightning eMotors Board of Directors and Strategic Advisory Board, and work closely with Lightning eMotor’s management team, to provide continued support and guidance on audit, governance, financing, M&A in accelerating its growth.

Looking to the Future GigCapital Global to Continue Launching and Driving PPE Funds The rich, existing pipeline from three years of GigCapital Global search, in particular the actionable large funnel from GigCapital2 and GigCapital3 searches, anchors the inception of additional PPE funds. GigCapital Global’s team will remain focused on TMT and ESG sectors, embracing today’s Digital Transformation and Sustainable Development Goals, to shape a better society and healthier environment. Our Proven Leadership Team The GigCapital Global team is a very experienced group of entrepreneurs and executives comprising former CEOs, senior- level corporate finance and SEC accounting executives, technical experts and industry renowned and respected thought-leaders that bring expertise and insights across all aspects of company management Dr. Avi Katz Founding Managing Partner GigCapital Global CEO, GigCapital3 Executive Chairman, GigCapital2, 3 Dr. Raluca Dinu Founding Managing Partner GigCapital Global CEO, President, GigCapital2 Neil Miotto Partner, GigCapital Global BOD Member, GigCapital2, 3 Peter Wang Chief Technical Advisor SW, GigCapital Global BOD Member, GigCapital3 Chief Technical Advisor HW, GigCapital Global BOD Member, GigCapital3

Certain statements in this company overview may constitute forward-looking statements for purposes of federal securities laws. Our forward-looking statements include, but are not limited to, statements regarding our or our management team’s expectations, hopes, beliefs, intentions, plans, prospects or strategies regarding the future. Any statements contained herein that are not statements of historical fact may be deemed to be forward-looking statements. In addition, any statements that refer to projections, forecasts or other characterizations of future events or circumstances, including any underlying assumptions, are forward-looking statements. The words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intends,” “may,” “might,” “plan,” “possible,” “potential,” “predict,” “project,” “should,” “would” and similar expressions may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. The forward-looking statements contained in this presentation are based on our current expectations and beliefs concerning future develop-ments and their potential effects on us. There can be no assurance that future developments affecting us will be those that we have anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond our control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements, including, without limitation, statements about: searching for, engaging with and completing initial business combinations; our success in retaining or recruiting, or changes required in, our offcers, key employees or directors following initial business combinations; our executive offcers and directors allocating their time to other businesses and potentially having conficts of interest with our business or in approving initial business combinations, as a result of which they would then receive expense reimburse-ments; our pool of prospective target businesses, including their industry and geographic location; and the ability of our executive offcers and directors to generate a number of potential investment opportunities. Should one or more of these risks or uncertainties materialize, or should any of our assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. We undertake no obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as may be required under applicable securities laws. “Private-to-Public Equity (PPE)” and “Mentor-Investor” are trademarks of GigFounders, LLC, used pursuant to agreement. Contact UsHEADQUARTERS 1731 Embarcadero Road, Suite 200Palo Alto, CA 94303P: (650) 276-7040E: info@gigcapitalglobal.comwww.gigcapitalglobal.comwww.gigcapital2.comwww.gigcapital3.comwww.gigcapital4.com

Additional Information and Where to Find It

GigCapital3 filed an amended registration statement on Form S-4 (File No. 333-251862), which includes a prospectus with respect to Lightning eMotors’ securities to be issued in connection with the business combination and a proxy statement with respect to GigCapital3’s stockholder meeting to vote on the business combination (as amended, the “GigCapital3 proxy statement/prospectus”), with the U.S. Securities and Exchange Commission (the “SEC”). Lightning eMotors and GigCapital3 urge investors and other interested persons to read the GigCapital3 proxy statement/prospectus, as well as other documents filed with the SEC, because these documents will contain important information about the business combination. The GigCapital3 proxy statement/prospectus and other relevant materials for the business combination will be mailed to stockholders of GigCapitl3 as of the record date established for voting on the business combination.

Stockholders may also obtain a copy of the preliminary proxy statement/prospectus as well as other documents filed with the SEC by GigCapital3, without charge, at the SEC’s website located at www.sec.gov or by directing a request to Brad Weightman, Vice President and Chief Financial Officer, GigCapital3, Inc., 1731 Embarcadero Rd., Suite 200, Palo Alto, CA 94303, or by telephone at (650) 276-7040.

Participants in the Solicitation

Lightning eMotors, GigCapital3 and their respective directors and executive officers and other persons may be deemed to be participants in the solicitations of proxies from GigCapital3’s stockholders in respect of the proposed business combination and related transactions. Information regarding GigCapital3’s directors and executive officers is available in its final prospectus filed with the SEC under Rule 424(b)(4) on May 15, 2020. Additional information regarding the participants in the proxy solicitation and a description of their direct and indirect interests will be contained in the preliminary and definitive proxy statements/prospectus related to the proposed business combination and related transactions when it becomes available, and which can be obtained free of charge from the sources indicated above.

No Offer or Solicitation

This communication shall neither constitute an offer to sell or the solicitation of an offer to buy any securities, nor shall there be any sale of securities in any jurisdiction in which the offer, solicitation, or sale would be unlawful prior to the registration or qualification under the securities laws of any such jurisdiction.