Why bank stocks look 'outstanding'

More upside for bank stocks?

When asked why he robbed banks, Willie Sutton famously (if apocryphally) replied: "because that's where the money is." Over the past month, investors could say the same about bank stocks.

The SPDR bank ETF (KBE) is up 3.5 percent over the past month, seriously outperforming stocks as a whole. And according to technician Rich Ross of Evercore ISI, there are plenty of gains ahead.

"The banks actually look outstanding here on a technical basis," Ross said Thursday on CNBC's "Trading Nation."

On the chart, "we see that nice 12-month base of support, and we see a breakout from that bullish base," he said. And "the financials have actually held that breakout."

On the longer-term view at the bank ETF, Ross espies a "beautiful breakout for a very well-defined multiyear trading range."

"I think that sets us up for not only absolute performance from the banks, but relative outperformance against the broader market," he said. "I would be a buyer here."

Fundamentally, Andrew Burkly of Oppenheimer says that "banks are actually relatively attractive on a valuation basis," noting that the group is trading "right above book value, which is historically pretty cheap."

And as Burkly and Ross note, the banks may be the big beneficiaries of an eventual Federal Reserve rate hike, given that higher short-term rates will allow banks to earn greater returns on their holdings.