Major stock indexes are at multiyear highs but Wall Street does not seem to be running out of steam -- not just yet.

Robust corporate earnings and the Federal Reserve's promise to keep liquidity cheap have fueled the Nasdaq to a 10-year high and driven the Dow and the S&P to their highest levels since 2008.

We are clearly seeing signs of overbought conditions, but there is still a lot of optimism, especially after the S&P broke well above the 1,340 range. The next ceiling is really not until the 1,400 level, said Stephen Massocca, managing director of Wedbush Morgan in San Francisco.

Heading into May, a seasonally weak month for stocks, the Dow and the Nasdaq posted their best monthly performance since December. At Friday's closing bell, the S&P 500 was up 8.4 percent for the year.

With earnings season coming to an end, investors will shift their focus to economic data this week, especially the April employment report on Friday. Investors will scrutinize the jobs data for signs of improvement in the labor market.

After a mixed batch of data last week, investors would need to see a solid gain in jobs to believe in sustainable economic growth. Nasdaq's rebalancing of its index may also cause a bit of a stir in the market this week.

But despite the concerns, options investors were buying less protection against a market correction, according to James Dailey, portfolio manager of TEAM Asset Strategy Fund in Harrisburg, Pennsylvania.

It's surprising, but ironically, the put-to-call ratio on the S&P 500 rose late in the week of April 18th and early in the final week of April, but fell in the last few days.

We might see some reaction to the overbought conditions depending on the jobs number, he said, but still, that would be a minor pullback, maybe down to test the 1,340 levels.

Other economic data due this week include the ISM manufacturing data and domestic car sales on Monday, the ISM services-sector data on Wednesday, and weekly jobless claims on Thursday.

NASDAQ REBALANCING

Nasdaq will be rebalancing its benchmark Nasdaq 100 index on Monday, which will slash Apple Inc's weighting. The rebalancing will affect the relative weights of all the securities in the index and cause popular index-tracking funds such as the PowerShares QQQ to buy and sell shares to match the new composition.

Apple shares are likely to see some volatility, but unlike 10 years ago, hedge funds and traders start trading on this (the rebalancing) from weeks ahead, so it won't be a huge event on the overall market, said Jack DeGan, chief investment officer of Harbor Advisory Corp in Portsmouth, New Hampshire.

The CBOE Volatility Index or VIX <.VIX>, Wall Street's so-called fear gauge, was relatively low, ending Friday's session below 15, although it was up 0.9 percent for the day.

While conditions of being overbought and oversold can stick around for a while, as a trader, I feel this market is just too complacent. That is why I advocate looking at insurance, but also at this stage in the wave, ride it and not try to swim against it, said Joe Cusick, a senior market analyst at Chicago-based online brokerage firm optionsXpress.

The VIX usually moves inversely with the S&P 500, tracking options prices that investors are willing to pay as protection on the price moves of the underlying stocks.

So far, 324 of the S&P 500 companies have reported earnings, of which 73 percent were above analysts' expectations, according to Thomson Reuters data. In a typical quarter, 62 percent of companies beat estimates.

(Reporting by Angela Moon; Editing by Jan Paschal)

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