You might call what's happened to Banco Santander capital punishment. At least that’s how the Spanish lender's investors must feel after watching $33.4 billion in stock market value evaporate since Sept. 30, 2014.

The only surprise about the 29% hit to Banco Santander’s stock price is that it came as a surprise to anyone.

Savvy investors had to know the handwriting was on the wall when the bank announced with great fanfare the addition of Sheila Bair, former chair of the Federal Deposit Insurance Corp., to its board of directors one year ago.

This is the same Sheila Bair who suggested in her book Bull by the Horns that banks would "work better" if regulators would force banks to "raise capital requirements." Bair also promoted the book The Bankers' New Clothes, which revolves around one central message: Banks need more capital.

So it only made sense when the $1.2 trillion-asset Banco Santander unexpectedly raised $8.8 billion in new capital and announced it would cut dividends on Jan. 9, triggering a double-digit decline in its stock price. To be fair to the bank's investors, Santander had given investors a head fake in November 2014. Its third-quarter earnings report sent a strong message that the bank was adequately capitalized.

If there is any good news to come from losing $33 billion in market value, it is that Bair now knows firsthand that capital doesn't come free. It is easy for regulators and college professors to stand in their bully pulpits and preach to bankers that they need more capital. Yes, banks can add capital — but not without consequences to the shareholders whose interests must be protected by bank directors.

Prodded by bank regulators, Tier 1 capital ratios for U.S. banks are now at the highest level since the FDIC started tracking this data in 1984. For banks with assets greater than $10 billion, the Tier 1 capital ratio over the past three years is 34% greater than the average since 1984. For banks with assets between $1 billion and $10 billion, the Tier 1 ratio is 25% greater.

It's certainly true that banks are better capitalized in 2015 than they were in the years building up to the financial crisis. That is a good thing. However, too much of a good thing can be bad.

The banking industry is at a crossroads in 2015. After having to take directions from central planners in Washington for the past six years, let us hope that there is growing recognition among bank directors that the interests of investors cannot remain on the back burner if the industry is to be an engine of growth for the U.S. economy.

Consider the initial public offering of Citizens Financial Group in September 2014. The $130 billion-asset bank discovered only tepid demand for its shares. Though the bank raised $3 billion from its IPO, it wound up with a market capitalization of around $13 billion. Today the bank sells for 70% of book value.

Contrast that experience with that of Lending Club, the online lending marketplace that went public in December 2014. Investor demand for the stock pushed the share price up 50% in the days following the IPO. By the end of December, Lending Club’s market capitalization reached $8.5 billion, suggesting a valuation more than 50 times book.

Investors cannot be blamed if they are losing interest in bank stocks in favor of new financial intermediaries not hamstrung by the Dodd-Frank Act and Consumer Financial Protection Bureau rules administered by zealous regulators.

Based on my examination of the stock price performance of 340 U.S. banks in 2014, it appears that investors are most interested in banks that plan to be sold. Among the 16 banks with the best stock price performance in 2014, exactly half are banks that have announced their sale. And another six of those top-performing bank stocks are subject to wide speculation that they may soon be on the block.

If investors do not see a clear path to a 10% return on equity and a reliable dividend of at least 3%, expect more banks to sell in 2015. Capital is not free. Shareholders expect to be compensated.

As for Banco Santander, if you are curious about whether the bank has any more surprises up its sleeve, you may want to check Bair’s book. In its closing chapter, Bair lists her fixes for the industry. First on the list was capital. With that done, she should be ready to move onto another one of her ideas: "Break up the mega-institutions."

Maybe the punished investors in her bank will want to take her up on that recommendation.

Richard J. Parsons is author of Broke: America's Banking System and a retired executive of Bank of America, where he was in executive management roles for both the human resources and risk management departments.