Mutual funds are still the top investment in retirement plans, but ETFs are gaining ground.

Self-directed investors are opening up to exchange-traded funds in their retirement accounts, an analysis released Monday by Schwab found.

The institutional SDBA Indicators Report found that self-directed investors with brokerage accounts inside their retirement plan allocated 14% of their total portfolio to exchange-traded funds in the first quarter, up two points from a year ago.

Exchange-traded funds were also the only category to grow in net asset allocation, Schwab found.

Mutual funds are still the leading category, though. The report found 41% of overall portfolio allocation was to mutual funds. About a quarter is allocated to individual equities, while cash fell to 18%.

Average balances in self-directed brokerage accounts grew, too, Schwab found, increasing 1.3% over the fourth quarter and 10.6% over last year to $194,545.

Schwab noted that’s in spite of the S&P having its worst start to a year since 2009, confusion over the Federal Reserve’s intentions on interest rates and worries about China.

Among exchange-traded funds and mutual funds, investors allocated most of their dollars to large-cap funds, at 30% each. International equity ETFs are another favorite. Schwab found investors allocated 17% to those funds.

Commodity ETFs, however, lost favor. While there was relatively little change in ETF allocations in the first quarter, commodity allocations fell from 11% in the first quarter of 2013 to just 6%.

Mutual fund allocations were similarly stable. The biggest change was in taxable bond funds, which fell to 19% from 24%.

Information technology was the most popular sector for individual securities, followed by financials and consumer discretionary, unchanged from last year. Investors increased their allocation to health care to 11% from 9%.

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