Exchange-traded fund investors shook off the summer slump and put their money back to work in July.

Industry assets rose 6.5% in July as investors found investment opportunities overseas and also favored funds with large-cap investment styles.

Overall, the universe of 917 ETFs had $822 billion in outstanding assets as of July 31, according to State Street Global Advisors, which released its data Tuesday.

The international category emerged as the most productive, with $22.6 billion in assets. That number reflects inflows and accumulations or losses from market performance. Internationals also had the best performance among ETFs, as its outstanding assets increased by 13.2%. Indeed, while the Standard & Poor’s 500 returned a 7.1% performance in July, the MSCI EAFE and MSCI Emerging Markets indexes rose 9.5% and 8.4%, respectively.

ETFs that centered on style were also big winners. Assets in the size category came in at $11.4 billion, and were up 6.6%. That boost largely came from large-cap ETFs, which took in $6.6 million in assets during July, and were up 5.2%.

Fixed-income ETFs also stayed in positive territory. That category had $5.9 billion new assets, which were up 4.9%. It was a sign that investors are still unsure about the vitality of the U.S economy and equity market volatility, says Tom Anderson, head of ETF strategy and research at State Street Global Advisors, based in Boston.

Commodity ETFs however did not serve as a haven for jittery investors. Its assets dropped $3.7 billion, or 4.7%, giving it the steepest decline in assets for the month of July. The culprit was gold, whose prices dropped 6% for the month of July and dragged down the performance for the rest of that category, Anderson said.