What does the FIG group do(more details)?

Let me talk about banks in-depth and why they are one of the most revenue generating sub-verticals within an investment bank (at least at bulge brackets).

In terms of products, there is the usual M&A, DCM, ECM products, but also growing in popularity is structured products and balance sheet solutions. Most of the reason for the deal flow is because banks have to maintain a certain capital structure, but are also competing against Money Centers like JPM on things like scale and diversification that they need to do M&A, de-risk their balance sheet, and other areas of capital optimization so they can also grow and compete. In banks, you will primarily be working with strategics unless it is a divestiture, in which you may see some sponsor play.

For M&A, the industry is going through consolidation with currently more than 4,000+ banks, there is a lot of volume in play here and almost every week you will either see a credit union acquisition or a small bank merger ~$100MM - $200MM being advised by smaller investment banking franchises like KBW, Piper Sandler, Stephens, or Raymond James. Given just the sheer number of banks, there is often more pitching to clients and understanding the other banks landscape in geographies that you may not be familiar with, but the banks you cover are. Now in terms of larger M&A, $1Bn+, the market has generally been slow because of recent and incoming regulatory changes like Basel III End Game, the latest DOJ / OCC merger consideration changes, and sometimes consent orders that block these larger banks from doing M&A (e.g., TD will probably be out of the market for a while given their fine, asset downsizing, and asset cap in the U.S.). One of the largest considerations is what is called Tailoring Rules from Dodd-Frank, such that banks above a certain threshold have to be subject to additional regulations such as a long-term debt requirement past $100Bn in assets. Combining these considerations, plus the need to be well capitalized, still making a profit, and competing on scale with JPM shows how much consolidation there needs to be in the industry just due to the set-up.

For DCM, we can talk about traditional debt products but also structured products. As mentioned before, banks are continuously looking for ways to optimize their capital structure because it would be a concern if they did not meet certain capital requirements (especially when they do stress testing). Often times, traditional debt products such as senior debt and subordinated debt are merely just renewals (as well as revolving credit facilities for trust banks), so it is purely a volume game. DCM makes up a lot of the revenue in the banking sub-vertical purely due to its volume and coupled with investment banks making anywhere from $0.2MM - $0.5MM per transaction that lasts a week, it does bring in a lot for the firm. However, if your DCM team is fairly independent, you will see a lack of work here.

In terms of structured products, this is a "recent" development in the banks space, but it is more about banks being able to optimize their balance sheet either for capital or retained earnings. The theme here is that private credit and other alternative asset managers are buying loans and seeking partnerships with banks to take their loans off-balance sheet. Whether it be through a traditional loan sale, a synthetic risk transfer, or a forward flow, the structured products group within FIG will help banks improve their capital positioning by doing these transactions and partnering up with potential non-bank buyers (typically). 

For ECM, one has to recognize that a lot of these banks are public -- even the very small ones that might just be OTC banks. Therefore, a lot of the deal flow in ECM is often either growth capital or follow-on capital to improve the capital positioning of the bank. IPOs are few and far and there are very few relatively size banks that would be a good IPO candidate for a bulge bracket to take on.

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I honestly have not found any good free resources to get really in the weeds of technical bank modeling -- you will get the gist of it from these courses online, but the nuanced stuff including AOCI accretion, Durbin, etc. you will just have to pick-up on the job. KBW produces a banking primer every 2 years or so that you might be able to get your hands on. In-terms of general resources, American Banker is good and just general S&P news updates.