Financial ETFs are among the best-performing sectors so far this year after solid fourth-quarter earnings from major banks and on expectations the economy will continue to improve in 2013. However, a narrowly-focused fund tracking broker-dealer firms is leading the pack.

The the iShares Dow Jones U.S. Broker Dealers Index Fund (NYSEArca: IAI) is up about 18% year to date.

“This ETF provides an opportunity for investors to participate in the recovery of the capital markets industry without taking on firm-specific risks,” Morningstar says in a profile of IAI. “This ETF’s targeted (and unique) exposure might appeal to those seeking a surgical way to gain access to some of the marquee names in the investment-banking and brokerage business.”

It notes the “broker/dealer” rubric covers a wide variety of firms, including Wall Street banks with large trading businesses, retail and online brokers, exchanges and market specialists.

The fund’s top three holdings are Goldman Sachs (NYSE: GS), Morgan Stanley (NYSE: MS) and NYSE Euronext (NYSE: NYX). [ETF Spotlight: Broker-Dealers]

Bank ETFs have also been solid performers so far in 2013.

“Progress seen in the past one year gives a clear growth indication for the U.S. banking sector. Besides contraction in provisions for credit losses and cost containment, a marked recovery in the equity markets and consequent revenue growth led most of the banks to report higher-than-expected earnings,” Eric Dutram wrote for Zacks.