Over the next month, banks will be releasing results for the second quarter. In advance of these releases, let's take a moment to review the state of some of these banks as of the end of Q1.

Today, we'll look at Associated Banc-CorpĀ (UNKNOWN:ASBC.DL), a $24.8 billion bank headquartered in Green Bay, Wisconsin, that will release second-quarter earnings this Thursday. You can find information on other banks at my Motley Fool article feed, available here. All data in this analysis was sourced from the FDIC's Quarterly Banking Profile and S&P Capital IQ.

When I evaluate banks, I follow a model made famous by former Wachovia CEO John Medlin: soundness, profitability, and growth. As investors, we then look at valuation and the potential for investment after gaining a better understanding for each bank.

Soundness refers to the bank's asset quality. Generally speaking, this means loans. If a bank makes loans that are never repaid, that bank will fail, and fail quickly. The best banks put risk management first, ensuring that shareholder capital is protected if a portfolio of loans turns sour.

To measure this, we'll look at both non-performing assets and Associated Banc-Corp.'s provision for loan and lease losses. A simplified definition of non-performing assets is loans or other assets that have fallen seriously delinquent or are in foreclosure.

The provision for loan and lease losses is a reserve of money that the bank pulls out of its income each quarter to guard against future losses in the loan portfolio. Banks are required by regulation to maintain certain levels of reserves, but within that, management has plenty of wiggle room to over- or under-reserve. Over-reserving increases protection but hurts net income; under-reserving increases risk but keeps net income high.

ASBC Chart

For the quarter ending on March 31, Associated Banc-Corp. had 0.79% non-performing assets as a percentage of total assets. The FDIC reports that banks with total assets greater than $10 billion on average had 1.5% non-performing assets as a percentage of total assets.

Associated Banc-Corp reserved $5 million for the first quarter, which represented 2.10% of operating revenue. That compares with 5% for the $10 billion-plus peer group, according to the FDIC.

After establishing an understanding of a bank's risk culture and soundness, next we can focus on profitability. Any investment in a business is an investment in that company's future earnings, so profitability is a particularly important consideration for any bank investor.

The first question, perhaps most obviously, is whether the bank generates a profit at all. According to data from the FDIC, 7.3% of U.S. banks failed to generate a profit at all in the first quarter. That's one in every 14 banks!

For Associated Banc-Corp, the first calendar quarter of 2014 fortunately wasn't that bad. The company generated total net revenues of $238.5 million for the quarter -- that is total interest income plus non-interest income minus interest expense.

Over the past 12 months, Associated Banc-Corp has generated $945.8 million in total net revenue. Of that revenue, 69% was attributable to net interest income, the difference between interest earned on loans and paid out to depositors. The remaining 31% was through fees, trading, or other non-interest revenue sources.

The bank was able to turn a profit margin of 20% on that revenue.

For the first quarter, the company reported return on equity of 6.2%. Of the banks covered in this series of articles, the average return on equity was 8.9%. The FDIC reports that the average ROE for U.S. banks with total assets greater than $10 billion was 9.1%.

ASBC Return on Equity (TTM) Chart

The bank has a healthy revenue mix, and its profit margins are on par with the rest of the industry. That said, its ROE is disappointing even in light of the clearly conservative credit culture discussed in the soundness section of this analysis.

Leverage is a double-edged sword for banks and could easily fit into either the soundness or profitability categories. We'll call it a subset of both and discuss it here.

Leverage is just part of the game with banks, so if you're a conservative investor who really focuses on conservative capital structures, the banking industry may not be the best place for your money. Adding leverage is an easy way to juice return on equity, which is, generally speaking, a good thing. The bank increases assets and thus earnings, while maintaining a lower capital level.

The result is a higher numerator, a constant denominator, and a larger return-on-equity number. The math does the heavy lifting for you.

On the flip side, too much leverage can put the bank on thin ice if the loan portfolio takes a turn for the worse. A stronger equity base protects the bank from bankruptcy and bailouts, two outcomes that are both politically charged and downright terrible for shareholders.

Banks use all kinds of esoteric and overly complex accounting methods to determine leverage. We'll keep it simple here with an old-fashioned assets-to-equity ratio. The lower the number, the less levered (and more conservative) the bank.

Associated Banc-Corp's assets-to-equity ratio comes in at 8.6. The average of the 62 banks analyzed in this series of articles was 9.1.

The bank's below-peer-leverage ratios are at least partially to blame for the company's disappointing ROE; however, at 8.6, the company is certainly not underlevered.

ASBC Assets To Shareholder Equity (Quarterly) Chart

Growth and valuation
Associated Banc-Corp saw its revenues decline by 8.8% over the past 12 months. That compares with the 5.7% average increase among the 62 banks analyzed.

This change in revenue corresponded with a 1.5% increase in net income over the same period. The peer set averaged 14.1%.

Fifty-four percent of all U.S. banks saw year-over-year earnings growth in the first quarter.

The decline in revenues came in the face of an increase in both total assets and net interest income for the quarter. What, then, is to blame for the drop-off in income? It was a precipitous drop in mortgage banking fees to the tune of 65%.

Moving now to valuation, Associated Banc-Corp. traded at a forward price-to-earnings ratio of 16.0, according to data form S&P Capital IQ. That compares with the peer set average of 16.67.

Associated Banc-Corp's market cap is, at the time of this writing, 1.5 times its tangible book value. The peer set average was 1.9.

Many investors use a general rule of thumb of buying a bank stock when the price-to-tangible book value is less than 0.5 and selling when it rises above 2. For me, that method is just way too oversimplified.

It sometimes makes sense to pay a premium for a bank stock that places a high value on credit culture and asset quality. These banks will survive and prosper while others fall by the wayside. That security can be worth a premium. Likewise, a bank that relies heavily on leverage to achieve above-average return on equity may not be worth the price, even if price-to-tangible book value is low. That risk may not justify even a healthy discount in price.

Based on the factors we've discussed here -- soundness, profitability, and growth -- Associate Banc-Corp appears to be undervalued.

The bank trades at a very low price-to-book value, despite its above-average credit portfolio, conservative leverage, and strong profitability. The weakness in ROE and growth are both attributable to the decline in mortgage banking fees, a decline that was extremely steep in the quarter and likely short-term in nature.

Associated Banc-Corp is a well-run bank with excellent fundamentals, and it's priced at a very attractive discount.