UPDATE 1-Dropbox files for IPO of up to $500 million

(Adds background on company, details from filing)

Feb 23 (Reuters) - Data-sharing business Dropbox Inc on Friday filed for an initial public offering of up to $500 million with the U.S. Securities and Exchange Commission.

The company said it plans to have its common stock listed on the Nasdaq under the ticker symbol "DBX". http://bit.ly/2omUnih

Dropbox, which started as a free service to share and store photos, music and other large files, is facing heated competition from technology giants including Alphabet Inc's Google, Microsoft Corp and Amazon.com Inc .

Dropbox reported 2017 revenue of $1.11 billion, compared with $844.8 million a year earlier. The company's net loss narrowed to $111.7 million from $210.2 million.

The California-based digital storage firm with 11 million paid users across 180 countries said that about half of its 2017 revenue came from customers outside the United States.

Goldman Sachs & Co LLC, J.P. Morgan and Deutsche Bank Securities are some of the leading underwriters for the IPO.

The amount of money a company says it plans to raise in its first IPO filing is usually a placeholder. (Reporting by Laharee Chatterjee in Bengaluru)