Traders work on the floor of the New York Stock ExchangeVia Ryan Vlastelica NEW YORK (Reuters) – The S&P 500 closed flat on Wednesday, with a four-day rally within the index simply barely coming to an finish after Procter & Gamble minimize its outlook, although some positive earnings restricted the decline and eased issues that valuations had become stretched. The Nasdaq rose for a fifth straight session, boosted through robust outcomes at TripAdvisor, while the Dow felt the power from P&G and ended the day reasonably lower.