Global markets are fighting back in the face of Trump uncertainty

After a brutal beatdown on Wednesday, investors are wasting no time picking themselves up off the mat.

During pre-market trading, the S&P 500 looked to be headed for a second straight drop following former FBI director Robert Mueller's appointment as special counsel to investigate Russian efforts to influence the November election. But the index recovered in early trading on Thursday, gaining 0.4%.

The relief rally can also be seen elsewhere in global markets. Safe haven assets gave back some earlier gains as gold decreased 0.2% and the yen slid 0.6% versus the US dollar.

However, the relief did not translate overseas, as the Stoxx Europe 600 dropped 0.7% during regular trading hours, while the MSCI All-World Index lost 1.2%.

The relatively muted reaction is a far cry from what was seen on Wednesday, when the S&P 500 dropped 1.7%, its biggest decline since September 9, and a stock market fear gauge spiked almost 50%.

The snappy recovery in stocks should be of little surprise, considering US equity investors have made a habit of buying on weakness throughout the eight-year bull market. Following the United Kingdom's vote to leave the European Union last June, the S&P 500 fell 5.3% over two trading sessions, only to make up those losses in about a week.

The same dynamic was in play when China unexpectedly devalued its currency in August 2015. After the S&P 500 underwent an 11% correction, traders bought the dip and restored the benchmark to its pre-sell-off levels within about two months.