AFP/Getty

AFP/Getty

Amazon's (AMZN) made-up shopping Prime Day holiday starts tomorrow – but investors are already counting their profits.

Shares of Amazon Tuesday are up $ 10.02, or 2.2%, to $ 465.88 to a record high ahead of the company's special sale that's planned for tomorrow to stoke summer sales. That stock price increase puts $ 4.7 billion in the pockets of Amazon's investors – even before a single dollar is made by the company.The company now sports a market value of $ 217 billion.

Investors appear bullish Amazon is onto a new way to gin up consumer demand in the dead of summer. Consumers are already busily searching the Internet to see what will be put on sale – and Walmart (WMT) is responding with deals of its own.

What's most impressive is that Amazon's shares have already been soaring this year. Shares of the online retailer are up nearly 30% in a powerful rebound as investors are eager to jump into stocks with growth.

And Prime Day – is seen as a prime way to get growth.

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Follow Matt Krantz on Twitter at @mattkrantz