The S&P 500 has hit record levels this year and many stocks have generated fantastic returns for investors. But there's been no shortage of struggling investments, either. Many companies that have been finding it difficult to grow and that may not have any near-term catalysts on the horizon have seen their shares fall sharply this year.Among the S&P 500's worst performers thus far in 2024 are Walgreens Boots Alliance (WBA -2.35%), Moderna (MRNA -2.23%), and Intel (INTC -2.27%). Below, I'll look at just how ...