Both US stocks and Treasury yields rallied on Wednesday, after the Federal Reserve left interest rates unchanged at 0-0.25%. Fed Chairman Jerome Powell explained that even though there is economic progress, it is still not enough to provoke a change in monetary policy.

So, by the end of the US session, the S&P 500 rose 0.15%, with Alphabet posting the largest gain amid a better-than-expected sales report.

However, investors are still worried about the growing COVID-19 cases caused by the highly infectious delta variant, as well as on the potential for monetary tightening. Both threatens global economic recovery.

"While the economy appears to be gradually approaching, the Fed has yet to see enough data to warrant a significant policy change. We expect markets to remain volatile in the near term, largely due to the remaining earnings reports this season, key economic data and the pace of progress in reducing the global pandemic," AXS Investments CEO Greg Bassuk said.

On Tuesday, the five-day rally that pushed major US stocks to record highs stalled as investors were waiting for the earnings reports of Alphabet, Apple and Microsoft. Alphabet gave the biggest boost to Nasdaq 100 on Wednesday, but Apple offset it by saying that its sales could slow in the next quarter. Meanwhile, Microsoft fluctuated between gains and losses, while Facebook soared to an all-time high prior to its post-market release.

Other major US stocks, such as Boeing, also rose yesterday. McDonald's, on the other hand, posted a loss for the first time in seven sessions amid concerns over its margin forecasts.

So far, nearly 90% of S&P 500 companies that reported second-quarter results exceeded analysts' earnings estimates.

Other important events for this week are:

- Amazon earnings report;

- unemployment report in Germany (Thursday);

- data on US GDP and jobless claims (Thursday).

- GDP and CPI report from Germany (Friday).