Amazon and Alphabet, formerly known as Google, had their shares boosted in value by enthusiastic investors after both companies bettered profit forecasts.
Amazon defied expectations of a loss by posting a reported profit of $US79million ($NZ116.20million) for the three months ended September.
The latest result came after the $US92million the company scored in the second quarter.
The profits came on a 23.7% year-on-year gain in total sales to $US25.4billion.
Amazon shares rallied by 10.7% yesterday to reach $US624.50.
The profit news came as Amazon faced pressure to deliver more value to shareholders, despite founder Jeff Bezo's strategy of investing in a vast array of projects - from online video and music to its own smartphones, and delivery drones to business email.
Alphabet shares reached their highest-ever level in after-house trading, rising 11% to $US722.53.
Investors have been pressing the company to return more of its cash pile but the announcement the company will buy back up to $US5.09billion of its Class C shares came as a surprise.
Mature technology companies such as Apple and Microsoft have come under intense pressure in recent years to give back more cash to investors.
The company's reported profit was boosted by strong gains in mobile search and YouTube advertising, as it kept a tight lid on expenses.
Third-quarter revenue rose to $US18.7billion from $US16.52billion in the previous corresponding period.
Reported profit rose to $US3.98billion from $2.74billion in the pcp.
The company's results are the first since Google changed its name to Alphabet on October 2.
Microsoft reported a modest rise in profits for the quarter, saying in a briefing its new focus on cloud-based software was delivering results.
Profit in the quarter rose 2% to $US4.6billion while revenue fell 12% to $US23.2billion.
''We are making strong progress across each of our three ambitions by delivering innovation people love,'' chief executive Satya Nadella said in a quarterly briefing.
