Giant financial conglomerates were at the epicenter of the global financial crisis. The U.S., United Kingdom and European Union provided more than $10 trillion of capital infusions, guarantees and emergency loans to stabilize their financial systems and rescue failing megabanks — including Citigroup, Bank of America, Wachovia, Lloyds, RBS, UBS, Commerzbank and ING.

After the financial crisis reached its peak in 2008, central banks in all three jurisdictions adopted zero or negative interest rate policies and expanded their balance sheets by more than $5.5 trillion. Those extraordinary monetary policies were designed, in part, to reduce borrowing costs for megabanks and increase the value of troubled assets held on their balance sheets.

Despite the unprecedented bailouts of megabanks during the crisis, supporters of financial giants continued to propagate the myth of the "good" megabank. Advocates pointed to JPMorgan Chase, Deutsche Bank and Wells Fargo as "good" megabanks that seemed to emerge relatively unscathed from the crisis. Those three institutions were cited as proof that universal banking on a global scale could still provide benefits to society. Recent events have thoroughly debunked that claim.

In 2012, JPMorgan Chase suffered more than $6 billion of losses from its "London Whale" bet on high-risk derivatives, which the bank at first tried to hide from regulators and investors. JPMC has paid more than $40 billion in fines and legal settlements as the result of wide-ranging allegations of misconduct that cover the gamut of its retail, commercial and capital markets activities. Most recently, JPMC settled charges that it violated the Foreign Corrupt Practices Act by hiring hundreds of Chinese "princelings" to win business deals in China.

Deutsche Bank has already paid more than $10 billion in fines and settlements arising from similar charges of misconduct. It reportedly faces billions more in penalties from the Justice Department for mortgage-related fraud. With a huge exposure to high-risk derivatives, Deutsche Bank is widely viewed as the most vulnerable global megabank.

Wells Fargo has also paid more than $10 billion in fines and settlements. Recent disclosures about Wells Fargo's relentless cross-selling programs have laid bare a toxic culture, which pressured employees to open as many as 2 million unauthorized accounts. The creation of those bogus accounts resulted in unlawful fees and identity theft affecting tens of thousands of customers.

The scandals at JPMC, Deutsche Bank and Wells Fargo confirm that global megabanks are not just too big to fail but also too big to manage or regulate effectively. Unfathomable size and complexity are only two of the fatal flaws of megabanks. Financial giants also generate disastrous conflicts of interest by mixing traditional banking with high-risk capital markets activities, and by relying on short-term, bonus-driven compensation schemes.

The manifold conflicts of interest embedded in global megabanks are virtually guaranteed to produce compromised corporate cultures. Megabanks wield enormous influence that spreads their compromised cultures to our political and regulatory systems through lobbying, campaign contributions and revolving-door employment opportunities. More than six years after Dodd-Frank's enactment, our financial regulators have still not issued final rules to bar megabanks from using compensation schemes that encourage excessive risk-taking. Is that a coincidence? I don't think so.

The business model for global megabanks has repeatedly failed and should be abandoned before it leads us into the next financial crisis. That business model allows megabanks to finance their speculative activities in the capital markets by exploiting explicit and implicit federal safety net subsidies. To expect managers and regulators to produce "good" megabanks is to ignore the lessons of history and fundamental laws of human nature.

Art Wilmarth is a law professor at George Washington University Law School.