Shadow banking  is a catch-all term for an industry that encompasses hedge funds, private equity firms and structured investment vehicles, which blossomed outside the conventional bank sector during the past decade. It accounted for as much as AED246.11tn ($67 trillion) of transactions globally last year. But many proved vulnerable to shocks during the financial crisis, which spilled over into the banking sector.
On Sunday, the Financial Stability Board (FSB), the body that coordinates international banking standards and which is best known for the Basel rules governing banks' capital adequacy, began a consultation for oversight of financial firms that do not fit into the traditional categories of banking, insurance and pension funds. 
"Experience from the crisis demonstrates the capacity for some non-bank entities and transactions to operate on a large scale in ways that create bank-like risks to financial stability," said the FSB.
Family offices, which manage the private wealth of the richest citizens in the Arabian Gulf, were not explicitly named by the FSB, but many bankers have noted that their increased level of sophistication is leading them into areas often associated with shadow banking.
The FSB, which was established in 2009 as an offshoot of the G20 London summit, advises countries on how to safeguard their financial systems against shocks. It is an expanded version of the Financial Stability Forum created by the G7 in 1999.
As a member of the G20 group of developed and emerging economies, Saudi Arabia sits on the FSB and would be obliged to comply with any new regulation.
Recommendations will be published next September, following a consultation with members to ascertain exactly which entities in each country fall into the shadow banking sector.
Regulators in other Gulf states are already working to better regulate family offices, which are rapidly becoming more sophisticated and making use of financial tools traditionally used by global investment banks.
The Qatar Financial Centre (QFC) published new rules governing single family offices last month, tightly defining what they can do under the terms of their licences.
The Dubai International Financial Centre Authority has a similar oversight role for family offices operating in the emirate's financial free zone.
There are difficulties in regulating how a family invests its own money, but ultimately the aim is to protect private investors and financial firms alike, said Shashank Srivastava, the chief executive of the QFC Authority.
"From a regulatory point of view, we want to make sure that the money manager is managing the money properly."
But Gulf regulators  should aim to ensure that rules for such investors are applied across borders, so as to avoid creating "pockets where you have fly-by-night operators coming in and offering products", added Mr Srivastava.
Hedge funds, private equity funds and structured investment vehicles have greatly expanded their presence in the region over the past decade.
Bankers say some Middle Eastern families have sought to expand their financial capabilities to include tools typically used by "shadow banks", such as securities lending and repurchase agreements. Both will be covered by the FSB's framework.
They are also hiring former investment bankers and advisers as in-house specialists, said Omar Mirza,the regional managing director for institutional business development at the Swiss bank Pictet. But they are not always conscious of risk management, he warned.
"The family offices have the option of taking a bet without considering the conservation side of capital," he said. "They'll tend to take bigger bets."
Pictet recently closed its Dubai-based private banking office to instead focus on institutional family wealth, while Société Générale has also launched a "private investment banking" arm to target a similar market.
But private bankers worry that family offices are requesting ever greater levels of leverage to reap higher returns on assets currently yielding zero or less in real terms.
"That's not good for the client and not good for the bank," said Gary Dugan, the chief investment officer for Asia and the Middle East at Coutts.
Clearer regulations for family offices could be good for Middle Eastern families, such as whether a will or Sharia should dictate how assets are transferred between family members, said Karim Ghandour, the managing director of MoneyLine Group, an adviser to family offices.
But many families burnt by the financial crisis  had become sceptical of the sophisticated investment products being now pitched by private banks.
"People became more realistic post-2008," said Mr Ghandour. "Las Vegas is over."