The maintenance of a Sell rating indicates a negative outlook on the stock by Goldman Sachs, suggesting that the analyst believes the stock may underperform the market or its sector. However, the increase in the price target from $50 to $56 suggests a slightly improved outlook on the company's valuation, possibly due to new data or a reevaluation of the company's prospects. This mixed signal could lead to short-term volatility in the stock price as investors digest the implications of the higher price target against the backdrop of a Sell rating.