Google shares gained 0.96 per cent to end at $761.78, giving the Internet giant a market capitalization of $249.1 billion. Microsoft meanwhile fell 0.91 per cent to $29.49, translating into a market worth of $247.2 billion.
Both remained well behind Apple, which shed 1.16 per cent to $659.39, meaning its market cap is just above $618 billion.
Google's stock price has climbed steadily this year as the California-based company bolstered its positions in key Internet growth areas with its dominant search engine, Android mobile operating system and YouTube video venue.
The shares got a boost last week from a Citigroup note advising investors that the Google stock price could "rise significantly in the 12 months ahead."
A note Monday from Trip Chowdhry at Global Equities Research said both Google and Apple have "strong momentum" in the mobile Internet sector while "developer interest in Windows Phone is almost non-existent."
Chowdhry added that Google's "innovation velocity far exceeds any other company."
Enthusiasm for Microsoft has been lukewarm, despite its upcoming launch of the Windows 8 operating system and a push into the tablet and phone markets.