King Salman’s close relatives not only rule Saudi Arabia. They are also in business with it.

A major Saudi investment firm founded by one of the king’s sons, and now chaired by another, owns a significant stake in a conglomerate that does extensive government business, including in a shipbuilding partnership with a French defense contractor. A smaller firm founded by another of his sons says it invests in health care, telecommunications, education and other regulated or state-funded fields.

None of that apparent conflict of interest seems to be against the law.

But now their brother, Crown Prince Mohammed bin Salman, is leading a sweeping crackdown against what he has labeled “corruption” that has swept up at least 11 princes from the House of Saud. But his immediate family’s complicated and mostly undisclosed business interests are raising questions about what that accusation means in a kingdom where the law has so far included little or no regulation of what other countries have labeled and outlawed as self-dealing.

Saudi laws, issued by royal decree or derived from Islamic law, have so far included little or no regulation of the sprawling royal family and its closest clients. The family has never disclosed the sources of its income, how much its members might take from the country’s oil revenues, how much they earn from state contracts or how they afford their lavish lifestyles.

King Salman has never explained where he got the money to buy as much as $28 million in London luxury homes, just as his son, Crown Prince Mohammed, has never said how he was able to plunk down more than $500 million for a 440-foot yacht he spotted one day and decided he had to own.