Reports suggest Uber Technologies, makers of the rideshare mobile app, is close to raising a round of funding which would value the company at close to $40 billion.

T. Rowe Price Group is said to be in discussions to become a new investor in the company, according to reports from Bloomberg Business.

Existing investor Fidelity Investments is also set to participate in the latest round of funding, they said.

Uber is raising at least $1 billion under the latest deal.

If Uber does completes the funding and acquire a valuation of $35 billion to $40 billion would more than double its $17 billion value from a June financing.

This was then a record valuation for a United States technology start-up in a direct investment round – ahead of other star investments including AirBnB and Dropbox.

Such a valuation would also put San Francisco-based Uber at about 1.5 times the capitalisation of microblogging service Twitter.

Somewhat more surprisingly, it also places the company alongside Delta Air Lines, while potential rival Hertz Global Holdings has a value of $11 billion.

Uber is believed to be raising money to finance its international expansion.

The company, founded in 2009 by Garrett Camp and chief executive Travis Kalanick, has rolled out its car-booking services to more than 220 cities worldwide.