* Q3 profit at S&P 500 companies rose, not fell: analysts
* UnitedHealth rises most in five years on upbeat forecast
* Netflix surges nearly 20 pct on strong subscriber growth
* Indexes up: Dow 0.56 pct, S&P 0.81 pct, Nasdaq 1.22 pct (Updates to early afternoon)
Oct 18 (Reuters) - Wall Street rallied on Tuesday, following a slew of market-beating results from marquee companies that led to the possibility that Corporate America could snap a four-quarter streak of declining profits.
Of the 52 S&P 500 companies that have reported results to date for the third quarter, 81 percent have reported earnings that have topped analysts average estimate, according to Thomson Reuters I/B/E/S.
Now analysts estimate earnings at S&P 500 companies rose 0.2 percent in the quarter, compared with their estimate of a 0.7 percent drop at the start of the earnings season. Profits at these...