Notably, Ms. Khatun added, the loans that are approved by bank directors with connections to the party that happens to be in power are “the ones that get defaulted, invariably.”

Here’s an example: Salman F. Rahman, one of Bangladesh’s wealthiest individuals and a co-founder of Beximco, a major business group that specializes in exports of pharmaceuticals and garments. A 2007 cable from the United States ambassador in Dhaka subsequently disclosed by WikiLeaks called Mr. Rahman “allegedly one of Bangladesh’s biggest bank loan defaulters.” He was imprisoned for fraud in 2007-8, under the caretaker government.

In an interview in his Dhaka office early last year, Mr. Rahman told me he owed about $800 million to state-owned banks. He blamed the previous government, led by the Bangladesh Nationalist Party — a staunch rival of the Awami League, which is in power today — for not servicing his debts. By the time we met, though, Mr. Rahman had become an adviser to Sheikh Hasina, the prime minister of Bangladesh and the president of the Awami League. And the Bangladesh Bank was now “restructuring” his debts, he said.

Mr. Rahman is no exception. Some $565 million in assets are said to have been looted from the state-owned BASIC Bank between 2009 and 2012, yet the scam’s suspected mastermind, a former chairman of the bank, wasn’t troubled by the anticorruption commission investigating the fraud, reportedly thanks to his political connections. Banking in Bangladesh is beholden to the politicians.

This is largely because state institutions are underfunded and weak. Technocrats, auditors, courts — all those traditional safeguards don’t have enough authority or muscle in Bangladesh to keep the politicians in check.

This, in turn, is due to the fact that Bangladesh has one of the smallest tax-to-G.D.P. ratios in the world, at less than 10 percent. Lack of infrastructure prevents the collection of income taxes. There are myriad taxes on corporations, but it’s easy enough to bribe one’s way out of paying them. Partly as a result, imports are subject to exorbitant fees — which only gives importers an incentive to finagle a way to avoid them.

Then there’s capital flight. If you loot state resources in a country like Bangladesh, you don’t want to risk losing it to someone else’s scams or to seizure by the government. And so you take the money abroad, far from the prying eyes of local tax collectors, preferably to a low-tax, low-transparency jurisdiction.