Adel al-Jubeir, the Saudi foreign minister, delivered the kingdom’s message personally last month during a trip to Washington, telling lawmakers that Saudi Arabia would be forced to sell up to $750 billion in treasury securities and other assets in the United States before they could be in danger of being frozen by American courts.

Several outside economists are skeptical that the Saudis will follow through, saying that such a sell-off would be difficult to execute and would end up crippling the kingdom’s economy.