Apple Inc. (AAPL), the world's most valuable company, is poised to push tech stocks and the overall market higher. Optimism over the company's future is prompting analysts to raise their earnings estimates and stock price targets for Apple, which reports results later this week, Barron's reports. This comes after strong results from three other big techs - Inc. (AMZN), Google parent Alphabet Inc. (GOOGL), and Microsoft Corp. (MSFT) - boosted the S&P 500 Index (SPX) last week. Apple's shares also jumped sharply. (For more, see also: Tech Earnings Drive Stocks Further Into Record Territory.)

Smartphone Stampede

Last week's surge in Apple's share price partially can be attributed to investor confidence stemming from strong earnings reports from fellow tech giants Google, Microsoft and Amazon. More importantly, Apple's iPhone X, its most advanced smartphone unveiled last month, finally was offered for pre-orders on Friday and soon sold out. Gadget-crazy consumers were undeterred by a hefty price tag that ranges from $999 to $1,149, depending on the features.

Many of the buyers may be current iPhone owners eager to upgrade. Market research cited by Barron's indicates nearly half of them are "excited" by the new model. Meanwhile, the pricing of the iPhone X is comparable to that for Apple's cheapest computers, given list prices of $999 for the lightweight MacBook Air and $1,299 for the most basic versions of the MacBook and iMac, per Apple's website.

$10 Billion In New Revenue

Analysts at research firm GBH Insights have raised their estimate of iPhone X pre-orders from 40 million to 50 million units, calling the order flow so far to be a "stellar success," Reuters reports. At the list prices quoted above, that translates to increased revenues of over $10 billion for Apple, nearly 5% of the company's current annual total.

Without mentioning specific numbers, Morgan Stanley expects this to be the biggest iPhone cycle in three years, according to an October 30 research note. There is one trend that could hamper demand. The same report notes that "maturing smartphone features" are spurring many consumers to keep their phones longer than the usual two-year upgrade cycle seen previously.

Morgan Stanley's most recent research report on Apple holds to an earnings estimate of $1.82, slightly below the consensus of $1.87. They rate the stock an overweight, and have a price target of $199. That's nearly a 20% gain from today.

Boosting the Market

Last week shows how strong performance of the big tech stocks can drive the markets. Shares of Amazon, Alphabet and Microsoft all posted big gains, driven by strong earnings reports. Their stock prices rose, respectively, by 11.7%, 3.0%, and 6.1% from the open on Monday, October 23 through the close on Friday, October 27. Meanwhile, Apple was up by 4.0%.

Their share price movements have a huge impact on the S&P 500, since they are its four biggest constituents by market cap. As of Friday's close, their respective percentage weights in the S&P 500 were: Apple, 3.81%; Microsoft, 2.92%; Alphabet, 2.78%; and Amazon, 1.98%. In fifth place is Facebook Inc. (FB) at 1.91%. Combined, these five tech giants account for 13.4% of the S&P 500. This data is as of October 27, per Note that Alphabet's weight is based on combining its class A shares (ticker GOOGL) and class C shares (ticker GOOG).

As might be expected, strong demand for the iPhone X is driving investor optimism about key Apple suppliers. Shares of these companies have risen in response, per CNBC.

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