* S&P 500 coming off biggest weekly gain since July
* Earnings seen driving trading, dozens of names report this week
* Indexes up: Dow 0.24 pct, S&P 500 0.31 pct, Nasdaq 0.52 pct (Updates to mid-afternoon, changes byline)
By Chuck Mikolajczak
NEW YORK (Frankfurt: HX6.F - news) , April 21 (Reuters) - U.S. stocks advanced modestly on Monday as investors showed hesitation in the wake of a strong rally last week and ahead of key earnings releases.
The S&P 500 posted its best week since July last week, boosted by results from such names as General Electric Co and Morgan Stanley (Berlin: DWD.BE - news) . If the index ends higher, it will be the fifth straight daily rise for the benchmark, its longest winning streak since October.
Of the 87 companies in the S&P 500 that have reported results through Monday, about 62.1 percent have topped earnings expectations, according to Thomson Reuters (Frankfurt: TOC.F - news) data, compared with the 66 percent average over the past four quarters. On the revenue side, 51.7 percent have beaten forecasts, below the 54 percent average over the past four quarters.
S&P 500 companies' first-quarter earnings are projected to have increased 0.8 percent from a year ago, Thomson Reuters data showed. The forecast is down sharply from the start of the year, when profit growth was estimated at 6.5 percent.
"We are certainly in a wait-and-see mode for earnings which can be volatile and therefore a lot of money is just waiting on the sidelines to see what happens," said Tim Ghriskey, chief investment officer of Solaris Group in Bedford Hills, New York.
"Certainly, companies that confirm the rest of the year guidance, even if they miss the first quarter, it's a good thing because there is still a lot of expectation that we are going to see the economy begin to accelerate and also do some catch-up from the weather-impacted first quarter."
Halliburton Co rose 2.9 percent to $62.69 after the oilfield services company reported earnings that beat expectations and gave a strong profit outlook. The Philadelphia oil service index rose 1 percent.
SunTrust Banks (NYSE: STI - news) gained 1.2 percent to $38.39 after its results, while Hasbro Inc (NasdaqGS: HAS - news) rose 0.7 percent to $55.00 after its earnings beat expectations, though revenue was under forecasts.
The Dow Jones industrial average rose 40.08 points or 0.24 percent, to 16,448.62, the S&P 500 gained 5.75 points or 0.31 percent, to 1,870.6 and the Nasdaq Composite added 21.487 points or 0.52 percent, to 4,117.003.
Investors are looking ahead to results from Netflix Inc after the market closes. The online movie renter was recently a trading favorite, soaring 300 percent last year as the S&P 500's biggest percentage gainer. The stock, stung by concerns it may be overvalued, has slumped recently alongside a broader decline in other high-flying names. Analysts will look to see whether the results justify its still-elevated price.
Dozens of S&P components will report this week, including such closely watched names as Apple Inc (NasdaqGS: AAPL - news) , Biogen Idec (NasdaqGS: BIIB - news) and Facebook Inc (NasdaqGS: FB - news) . A number of Dow components, including McDonald's Corp, AT&T Inc (NYSE: T - news) , Procter & Gamble and Caterpillar Inc (NYSE: CAT - news) , also report.
More than 30 companies in the Nasdaq 100 are slated to report, according to Nasdaq, a group that together represents more than half of the index's weight.
In company news, Britain's Sunday Times reported that Pfizer (TLO: PF-U.TI - news) Inc had approached AstraZeneca (NYSE: AZN - news) to propose a $101 billion takeover, an offer that was rejected. However, Astra's cancer drug pipeline is still considered a draw for Pfizer (NYSE: PFE - news) . Shares of Dow component Pfizer rose 2 percent to $30.85 while U.S. shares of Astra jumped 7.4 percent to $68.21.
Talks between Barrick Gold Corp and Newmont Mining (EUREX: NEMF.EX - news) Corp about a potential merger have hit a snag, but the companies remain keen to reach a deal and discussions are likely to resume, sources told Reuters.
Shares of Newmont rose 5.8 percent to $24.90 as the S&P's biggest percentage gainer, while U.S. shares of Barrick fell 3.3 percent to $17.39.
(Reporting by Chuck Mikolajczak; Editing by Nick Zieminski)