The tech-focused Nasdaq index closed 73.84 points higher at 5106.59.
The biggest winner on the index was Broadcom. Shares soared 21% following reports that Avago Technologies is close to buying the company.
Other US indexes also rose - recovering from steep falls on Tuesday.
The Dow Jones gained 121.45 points, or 0.7%, to 18,162.99, while the S&P 500 climbed 19.28 points to 2,123.48.
Alan Skrainka, chief investment officer at Cornerstone Wealth Management, said the market is in a "back and forth" mode with little clear direction.
"Yesterday there was some nervousness over the potential for a Greek default and today we have a little more buying," he said.
The Nasdaq's gain takes it almost 15 points above the prior record set on 24 April.
The index gained ground despite a 24% tumble for shares in handbag maker Michael Kors.
Fourth-quarter revenues rose 17.8%, its slowest revenue growth since December 2011.
The company predicted full-year revenues and earnings which fell below analysts' expectations.
Shares in Tiffany jumped 10.6% after the jewellery retailer's first-quarter profits beat expectations.
Net income fell to $104.9m in the quarter from $125.6m a year earlier, but this was not as bad as analysts had feared.
(Close): The Nasdaq share index rallied to a record after technology and healthcare stocks advanced, helped by optimism that Greece would not default on its debt.