Snapchat is reportedly looking to raise as much as $500m in a new funding round that would value the mobile messaging company at up to $19bn.

The latest valuation is a massive increase for the company, which Facebook offered to buy for $3bn in late 2013. 

Snapchat's previous funding round, completed late last year, valued the company at more than $10bn.

News agency Bloomberg quotes a source as saying that executives of the company, which allows its more than 100 million users to send messages that disappear after a few seconds, are in advanced talks with fund managers.

The investments being discussed would value Snapchat between $16bn and $19bn overall, Bloomberg reported.

Los Angeles-based Snapchat could not be reached immediately for comment.

The drastic increase in valuation comes as Snapchat continues to add to its active user base and extends its service. Last month it added videos and articles by mainstream media outlets such as CNN and ESPN, bringing Snapchat into closer competition with Facebook and Twitter.

It is also the latest evidence of a surge in venture capital financing for technology companies, that has produced some eye-popping valuations.

Even at $19bn, Snapchat would only be the third-most valuable tech startup that does not trade its shares publicly. 

According to research firm CB Insights, Chinese smartphone maker Xiaomi is worth $46bn and app-based taxi service Uber is valued at $41bn.