NEW YORK ( TheStreet) -- U.S. stocks have started the week with a nice vote of confidence but the terrain gets tougher from here.

Eighty S&P 500 companies are due to report before the closing bell sounds on Friday. The early reviews on the third quarter are worse than expected but it's easy enough to brush that off to small sample size. Over the next few days, the picture will clear up and nervous investors holding healthy profits for 2012 overall may decide to cut back on their equity exposure.

What's worth considering is that there's some evidence corporations have already started bailing out. Over the weekend, research firm TrimTabs noted that corporate selling, measured by new offerings and net insider selling, has totaled $12.4 billion so far in October vs. corporate buying (new cash takeovers plus announced buybacks) of $8.5 billion.

That's not a huge gap (and it doesn't factor in the Sprint ( S)/ Softbank deal) but there's more of a disparity going back to the start of September, when the tally is corporate selling of $62.7 billion vs. corporate buying of $34.5 billion, a $28.2 billion difference.

"Given the lofty valuations at which the overall U.S. stock market trades, we can hardly blame corporate America for ramping up its selling," the firm wrote.

The trend is especially concerning if the impact of buybacks on helping the major indices return to multi-year highs is factored in.

Sean Darby, chief global equity strategist at Jefferies, cited S&P data Monday saying S&P 500 constituents conducted $111.7 billion in buybacks in the second quarter, up from $84.3 billion in the first quarter.

" The unintended consequences of the reluctance of companies to invest in new capex but hoard cash at close to 1945 record levels is to buyback shares," he said. "Aside from low real interest rates, one of the main reasons why the US equity market has held up well is due to the squeeze on the stock free-float. Indeed, stock repurchases have offset stock withdrawals by households during the past six months."

Meantime, Brian Belski, chief investment strategist at BMO Capital, discussed his firm's call that stocks are "likely to take a breather between now and year end" on Monday, saying it's "unfortunate" this has been interpreted as a sell signal since BMO's year-end target for the S&P 500 is 1425, below the index's close at 1440 on Monday.

"While we expect the market to trade in a fairly narrow range for the next several months, we believe it is inappropriate for investors to approach US equity investing with an 'am I in or am Iout' strategy, particularly considering that correlation amongst stocks continues todecline near multiyear lows," he wrote, adding that "plenty of opportunities" still exist in equities for active and disciplined investors.

As for Tuesday's scheduled news, earnings season really starts to pick up in the a.m. withthree Dow components releasing results before the opening bell: Coca-Cola ( KO), Johnson & Johnson ( JNJ) and UnitedHealth ( UNH).

Goldman Sachs's ( GS) numbers will hit the tape bright and early as well and Thomson Reuters has tabbed the bank as a likely candidate for an upside surprise. The firm noted its research shows the consensus view has been moving higher since September and that the analysts who have been the most accurate in the past are particularly bullish this time around.

The average analyst estimate is for earnings of $2.12 a share from Goldman in the third quarter on revenue of $7.3 billion but Thomson Reuters said: "Two StarMine-rated five-star analysts are betting Goldman will do even better, with estimates of $2.70 and $2.75. Goldman's Q3 revenue estimates have moved higher since September as well, with the current mean value at $7.301 billion, and the revenue SmartEstimate 1% higher at $7.372."

Thomson's StarMine estimate is looking for a profit of $2.20 a share, roughly 4% above the mean view, and the firm notes a variation of more than 2% in either direction has historically resulted in an earnings surprise in that direction more than 70% of the time.

Other early reporters include Domino's Pizza ( DPZ), Forest Laboratories ( FRX), Mattel ( MAT), Omnicom ( OMC), PNC Financial ( PNC), State Street ( STT), W.W. Grainger ( GWW), and Wolverine World Wide ( WWW).

Two big tech names, both blue chips, report after Tuesday's close: Intel ( INTC) and IBM ( IBM).

Wall Street is looking for earnings of $3.62 a share from Big Blue on revenue of $25.38 billion. Jefferies, which has a hold rating and a $225 price target on the stock, is in line with the consensus view.

"We believe IBM had a strong quarter from software along with System x and System z servers," the firm said. "We estimate that the Services business saw an okay quarter relative to its peers given a tough macro environment. We believe IBM's cloud products are becoming more prominent and will see growth in storage."

With its stock up nearly 14% in 2012 and a streak of eight upside surprises on the line, IBM investors are no doubt expecting a bit more.

As for Intel, expectations are down since the no. 1 chip maker's warning in early September. The average estimate of analysts polled by Thomson Reuters is for a profit of 49 cents a share in the quarter on revenue of $13.23 billion.

In an earnings preview for the semiconductor companies, BMO Capital said even the expectations for fourth-quarter guidance are probably below the published numbers for the group. Here's the firm take on Intel: " Although estimates have come in a fair bit, we would like to see GM gross margin reset for us to begin to get more constructive on the stock. Despite the steady downward revisions, we are still below the Street for 2013 at earnings of $2.10 vs. now $2.17." Also slated to open the books after the bell are Apollo Group ( APOL), Cree ( CREE), CSX Corp. ( CSX), Intuitive Surgical ( ISRG), Sonic Corp. ( SONC), and United Rentals ( URI).

Intuitive Surgical's report bears watching after the company was upgraded to overweight at JPMorgan on Monday. The firm also lifted its December 2013 price target on the stock to $625, implying potential appreciation of 22% from Monday's close at $512.53. Share have gained 10.7% year-to-date.

"While there are clearly some headwinds to the Intuitive Surgical (ISRG) story, notably the recent dVP daVinci procedure decline and industry-wide European challenges, we find the risk/reward increasingly compelling, in light of the meaningful opportunities emerging in partial nephrectomy, cholecystectomy, colorectal surgery and other areas (thoracic, etc.) - which, collectively, should more than offset the dVP softness and drive upside to Street estimates for the next several years," JPMorgan said.

For the third quarter, Wall Street is expecting earnings of $3.50 a share from Intuitive Surgical on revenue of $534.9 million. JPMorgan was adamant that its call "is not about the quarter" but did add it thinks the risk is "to the upside" for both the third quarter and full year.

"We do not have enough conviction on the system placement number to say that one must go long in front of the print, and clearly, med tech pre-announcements to date have featured notable shortfalls (e.g., EW, NUVA, DXCM), which have been attributed, at least in part, to weakness in Europe and softer procedure volumes," the firm said.

Tuesday's economic calendar includes the consumer price index for September at 8:30 a.m. ET; the net long-term Treasury International Capital flow data for August at 9 a.m. ET; industrial production and capacity utilization data for September at 9:15 a.m. ET; and the National Association of Home Builders housing market index for October at 10 a.m. ET.

-- Written by Michael Baron in New York.

>To contact the writer of this article, click here: Michael Baron.

Disclosure: TheStreet's editorial policy prohibits staff editors, reporters and analysts from holding positions in any individual stocks.

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