The disruptive taxi-hailing app, already valued over $40bn, is aiming to raise between $1.5bn and $2bn in a private funding round according to report in the Wall Street Journal.
Such a valuation would set Uber on course to become the most valuable startup in history before being listed on the stock exchange. Facebook was valued at $50bn on its initial public offering price in 2011, however the app could well go beyond such a valuation after raising more than its targeted figure in two previous funding rounds.
Chinese manufacturer Xiaomi is currently the world's most valuable startup after it was valued at $45bn in its most recent round of funding.
However, unlike Facebook, Uber has also racked up hefty debt - around $5bn in five years. The San Francisco-based company has spent big on expanding its service around the world and setting up a number of separate businesses beyond its core taxi service such as shopping delivery app UberRush and UberFRESH which delivers fast food.
According to some reports, the company may even be considering a $3bn purchase of Nokia's Here mapping business. Chief executive Travis Kalanick has said he wants to create 50,000 jobs in Europe
In January Uber raised $1.6bn from Goldman Sachs' private wealth arm in January.