Shares in online search giant Google reached an all-time high Monday of $750.04 US, just three days before its 14th birthday.

The shares, which are up 13 per cent this year, closed up $15.39, or more than two per cent, at $749.38.

Google had been lagging much of the stock market earlier this year amid concerns about regulators' investigations into the company's business practices and its recently completed $12.4 billion acquisition of cell phone maker Motorola Mobility.

Google eased some of the worries about Motorola becoming a financial albatross last month when it announced plans to lay off about 20 per cent of Motorola's workforce, or about 4,000 workers.

Investors have also been betting that the antitrust investigations in Europe and the U.S. will be resolved without weakening Google's moneymaking prowess.

Google has also made strides with its Android mobile phone technology, which research firm IDC estimates dominated the global smartphone market in the second quarter, with a 68 per cent share, compared with Apple’s 17 per cent.

With files from The Associated Press