The S&P 500 has been on a bullish run lately, with three key factors contributing to its upward momentum. But should investors go long on this trend? Firstly, the US economy is showing signs of recovery from the pandemic-induced recession. The latest GDP figures show a growth rate of 6.4% in the first quarter of 2021, and the unemployment rate has fallen to 6%. This bodes well for corporate earnings, which are a key driver of stock market performance. Secondly, the Federal Reserve has signaled that it will maintain its accommodative monetary policy for the foreseeable future. This means that interest rates will remain low, which is good news for companies that need to borrow money to invest in growth. It also means that investors are likely to continue seeking higher returns in the stock market, rather than in low-yielding bonds. Finally, the Biden administration's proposed infrastructure spending plan could provide a boost to the economy and to certain sectors of the stock market. The plan includes investments in transportation, broadband, and clean energy, among other areas. This could benefit companies in the construction, engineering, and renewable energy sectors, among others. Taken together, these three factors create a bullish trifecta for the S&P 500. However, investors should still exercise caution before going all-in on this trend. The stock market is notoriously unpredictable, and there are always risks to consider. For example, inflation could rise faster than expected, leading to higher interest rates and a sell-off in stocks. The pandemic is still ongoing, and new variants could lead to renewed lockdowns and economic disruption. And geopolitical tensions, such as those between the US and China, could create uncertainty and volatility in the markets. In conclusion, the S&P 500 is currently experiencing a bullish trifecta that could continue to drive its upward momentum. However, investors should be aware of the risks and exercise caution before making any investment decisions. As always, diversification and a long-term perspective are key to successful investing.