You'll Never Guess Which Healthcare Stock Delivered the Best First-Quarter Performance in the S&P 500.

The first quarter was a difficult one for theS&P 500and for investors as a variety of concerns circulated -- from worries about the revenue potential of artificial intelligence (AI) companies to the pressures of turmoil in Iran. All of this pushed many investors to avoid AI players and other growth stocks and turn to companies seen as stable parts of the economy -- such as healthcare businesses. While many industries struggled in recent weeks, a variety of healthcare stocks soared -- from pharma giantJohnson & Johnsonto dialysis services providerDaVita Inc. But you'll never guess which healthc