The trading week is at an end, but over at investment banker Wedbush, the time to start buying banks has only just begun.

According to our data here at Motley Fool CAPS, where we've been tracking its performance for more than a decade, Wedbush is one of the best investors on the planet. Over the past 10 years, it's outperformed better than 87% of its peers, and beat the market by about 22 percentage points per pick.

This morning, Wedbush initiated coverage on America's regional banking sector. Assigning ratings to more than a dozen banks, Wedbush shrugged off the majority with mere neutral ratings. But there were a small handful of banks that Wedbush felt more strongly about. For example, the banker assigned outperform ratings to KeyCorp (NYSE:KEY), Huntington Bancshares (NASDAQ:HBAN), and Regions Financial (NYSE:RF).

Want to know why? You've come to the right place.

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The No. 1 choice: KeyCorp

Wedbush's reason for picking KeyCorp can be summed up quite simply, and does so thusly: "KEY trades at the lowest P/E in our bank group."

Trading at 10 times 2017 estimated earnings per share, "vs. our regional bank median at 12.3x," KeyCorp is quite simply the cheapest regional banking stock on Wedbush's radar today. Now, Wedbush acknowledges that the stock is cheap for a reason, suggesting investors are worried about the "integration risk" of KeyCorp not profiting sufficiently from its recent purchase of First Niagara. But Wedbush argues that "if Key can successfully integrate FNFG," this could lead to improvements in profitability that would lift KeyCorp "slightly above peer averages," and produce "above-average EPS growth" as well.

Given that KeyCorp is already expected to grow earnings at 9.4% annually over the next five years, it won't take much of an improvement to lift that growth rate past 10%, and give this 10 (forward) P/E stock a PEG ratio of less than 1.0.

Runner up: Huntington Bancshares

Huntington Bancshares stock makes a similarly strong showing at No. 2 on Wedbush's buy list. As the analyst explains, Huntington stock costs only 11 times 2017 estimated earnings. However, Huntington also carries "integration risk" from its purchase of FirstMerit.

Granted, too, "11 times earnings" is a valuation 10% more expensive than KeyCorp's 10 times valuation. But once again, Wedbush is looking for a successful integration of a regional bank's smaller prize to help boost both "profitability metrics" and "EPS growth" alike.

So what's the risk here? According to Yahoo! Finance data, analysts currently expect no better than 4.8% annualized earnings growth from Huntington. To get that number up to 11% or so, and thus yield an attractive PEG ratio, the "integration" of FirstMerit is going to have to go off swimmingly, and be far more successful than most investors think likely.

A perfectly viable alternative: Regions Financial

Wedbush views Regions Financial as slightly less attractive than either of the alternatives discussed above -- but it's hard to say exactly why. Granted, Regions stock sells for 11.6 times Wedbush's estimate of its 2017 earnings. But if that's slightly more expensive than Huntington's forward P/E ratio, well, at least consensus estimates call for Regions to grow its earnings slightly faster than Huntington, at 5.6%.

As for the prospects for nudging that growth rate higher, Wedbush argues that "RF has several initiatives under way to generate positive operating leverage." And given that "RF is one of the most asset sensitive banks in our group," the analyst believes that "any increase in rates will add additional earnings leverage" for the company -- presumably superior to what such an interest rate hike would give to KeyCorp and Huntington.

Final thought: New York Community Bancorp

In closing, I want to say a few words on New York Community Bancorp (NYSE:NYCB), one of several banks that Wedbush declined to recommend this morning, and rated only neutral.

The reasons for the analyst's pessimism on this one are pretty clear. For one thing, in contrast to profitable KeyCorp, Huntington, and Regions, New York Community Bancorp currently sports $0.09 per share in net losses for the past year. (Additionally, the analyst warns that NYC Bancorp is likely to post "flat EPS growth" through the end of this year.)

But I have to point out that while New York Community's numbers are pretty unattractive today, I'm not all that enthused with the valuations on KeyCorp, Huntington, or Regions stock, either. Wedbush bases its recommendations on all three stocks on the profits they will earn in 2017, but those final numbers won't be confirmed for more than a year, and are anything but certain.

Meanwhile, trailing P/E ratios show KeyCorp, Huntington, and Regions stock all valued at or near 13 times trailing earnings today. And none of these stocks is projected to grow earnings at anything approaching 13% or better over the next five years.

From my perspective, that works out to PEG ratios of 1.3 or so on all three of Wedbush's recommendations. And that's too expensive to justify recommending any of them.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.