May was a month of relatively modest returns for U.S. stocks. The S&P 500 (SPY), the Russell 2000 (IWM) and the Nasdaq 100 (QQQ) were all little changed, while U.S. Treasuries were essentially unchanged. International stocks performed better with developed markets gaining around 3% and emerging markets adding 2%.

The big story of the month, however, was the commodities market. Prices on everything from lumber to steel to wheat to oil have been soaring. Industrial commodity prices in some cases have come crashing back down to earth, but precious metals have done well as inflation expectations continue to rise and the dollar continues to fall.

Here's the list of the top 30 performing ETFs for the month of May 2021.

Top Performing ETFs for May 2021

Top Performing ETFs for May 2021

The theme of this month's top performer list is pretty clear - precious metals miners and oil. The top 14 ETFs on this are all focused on either precious metals or energy related companies. For the month, crude oil prices rose about 5%, while gold and silver both gained about 8%.

The iShares MSCI Global Silver & Metals Miners ETF (SLVP), which targets companies that mine silver or other metals, tops the list, but there are any number of similar ETFs within a percent or two of the top spot. Silver-focused ETFs, including the ETFMG Prime Junior Silver Miners ETF (SILJ) and the Global X Silver Miners ETF (SIL), also delivered 16-17% gains.

Gold miners also consistently delivered double digit returns. The iShares MSCI Global Gold Miners ETF (RING) narrowly topped its peers. The twin funds from VanEck - the VanEck Vectors Gold Miners ETF (GDX) and the VanEck Vectors Junior Gold Miners ETF (GDXJ) - appear as do others, such as the Global X Gold Explorers ETF (GOEX), the Sprott Gold Miners ETF (SGDM) and the Amplify Pure Junior Gold Miners ETF (JGLD).

Oil-focused ETFs were also top performers. We saw funds, such as the VanEck Vectors Oil Services ETF (OIH), the iShares Oil Equipment & Services ETF (IEZ) and the Invesco Dynamic Oil & Gas Services ETF (PXJ) appear in the top 10, but the top oil ETF was the more broadly-based Invesco S&P SmallCap Energy ETF (PSCE), which gained 17%.

We also see a fairly diverse mix of individual country ETFs posting significant returns. The Franklin FTSE Brazil ETF (FLBR) and the VanEck Vectors Brazil Small-Cap ETF (BRF) both rallied as the country continues to slowly rebound from the COVID pandemic. Brazil has been one of the hardest hit regions of the world and still has a lot of work to do to recover, but infection rates are coming down and the country's central bank began raising rates suggesting a slow return to a more normalized environment.

The iShares MSCI Poland ETF (EPOL), the iShares MSCI UAE ETF (UAE), the Columbia India Consumer ETF (INCO) and the iShares MSCI Russia ETF (ERUS) are the other individual country ETFs represented.

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