Cooley has taken the lead role on a $3bn (£2.4bn) initial public offering (IPO) announced on Thursday (2 February) by Snap Inc, the parent company of social media app Snapchat.

The listing by Snap, whose co-founder and CEO Evan Spiegel is the son of a partner at West Coast US law firm Munger Tolles & Olson, could be the largest technology stock offering in 2017.

Cooley has been a long-time legal adviser to the company, which is based in the Silicon Beach neighborhood near Los Angeles in Venice, California. Snap officially disclosed its plans to list on the New York Stock Exchange in a prospectus filed with the US Securities and Exchange Commission (SEC).

Cooley corporate and securities partner Eric Jensen in Palo Alto, California, serves as the firm's relationship partner to Snap, and last year advised the company on a $1.8bn (£1.4bn) fundraising. He is working on Snap's IPO with Cooley corporate partners David Peinsipp and Seth Gottlieb. Other Cooley lawyers advising on the matter include executive compensation and benefits partners Barbara Mirza and Renee Deming, tax partner Mark Windfield-Hansen, M&A and public companies partner Craig Menden, and securities litigation partner John Dwyer.

Securities filings by Snap do not yet provide an estimate of the legal fees and expenses the company expects to incur by going public. Snap's prospectus does state that GC&H Investments LLC – an entity comprised of Cooley partners and associates – owns "239,800 shares of our Class A common stock and 239,800 shares of our preferred stock". The latter will be converted into the same amount in shares of Class B common stock upon the IPO's closing. (PEHub reported in 2013 that GC&H Investments invests in startups on behalf of Cooley lawyers.)

Goodwin capital markets partners Richard Kline and An-Yen Hu are working with the firm's technologies company chair Anthony McCusker in advising Goldman Sachs and Morgan Stanley in their roles as underwriters for Snap's IPO. All three lawyers are based in the Bay Area.

Snap's prospectus lists general counsel Christopher Handman – a former Hogan Lovells partner hired by the company in 2014 – and associate general counsel Atul Porwal as handling matters for the company. Porwal previously spent four years as a Cooley associate, before joining Snap in 2015. Steven Hwang, another former Cooley associate, left the firm in early 2014 to become vice-president of corporate development at Snap. Two more former Cooley associates, Brian Camire and Edward Mata, serve as associate general counsel and strategy at Snap, respectively.

The SEC filing states that in October 2016, the company entered into an amended employment agreement with Handman, whose base salary last year was $475,000 (£381,000). The prospectus also includes a section detailing the company's relationship with Munger Tolles. John Spiegel, a litigation partner with the firm in Los Angeles, is the father of Evan Spiegel. The firm has previously handled work for Snap and John Spiegel's relationship with his son was the subject of a high profile story in LA Weekly in 2014.

Snap's IPO filing states that the company has paid Munger Tolles a collective $649,314 (£520,000) in legal fees during 2014, 2015 and 2016. Snap noted that John Spiegel "has not personally provided any material legal services to us". Spiegel senior, a leading lawyer to the entertainment industry, did not return a request for comment.

A suit filed in 2013 by a former Stanford University fraternity brother of Snap's founders revealed Cooley's early involvement for Snapchat. The classmate, Frank 'Reggie' Brown IV, claimed that Evan Spiegel and Bobby Murphy cut him out of credit for inventing Snapchat and that they sent him a "threatening" letter through Cooley.

Snap, which shortened its name last year, settled the litigation with Brown in 2014. Cooley is also listed as counsel to the company in another suit filed last summer by celebrity lawyer Mark Geragos, accusing Snap of violating the Communications Decency Act by not doing enough to bar sexual content on its platform.

Other firms that have represented Snap and its founders in the past include Quinn Emanuel Urquhart & Sullivan, which defended the company in the Brown suit, and Perkins Coie litigation partner Rebecca Engrav, who in 2014 helped Snap settle Federal Trade Commission charges that it deceived users about its data collection processes.