Evidence from March–April 2023 shows that depositor flight and contagion did spread to other U.S. regional banks, with substantial cash outflows and runs/near-runs:

• First Republic Bank: After the SVB and Signature failures in March 2023, First Republic experienced massive withdrawals. Its Q1 2023 filings reported over $100 billion in deposit outflows in March, largely tied to uninsured and wealthy depositors moving money after the SVB collapse. Multiple analyses characterized this as a classic modern bank run driven by contagion fears from SVB.
• Sector‑wide regional bank stress: In the weeks following SVB’s failure (mid‑March through April 2023), numerous U.S. regional banks—such as PacWest and Western Alliance—saw sharp deposit declines and intense market pressure, with reports of customers shifting funds to larger banks and money‑market funds for perceived safety. Regulators and financial press widely described this as contagion from SVB’s collapse affecting regional institutions, even where fundamentals differed.
• Aggregate data on small/medium banks: Federal Reserve and industry data released later in 2023 showed that smaller U.S. banks suffered material net deposit outflows in March 2023, while the largest banks and money‑market funds recorded inflows—consistent with the “flight to safety” and “why take a chance?” behavior the prediction described.

Because (a) contagion fears did spread, (b) multiple regional banks experienced substantial deposit outflows, and (c) at least one major regional (First Republic) suffered a run severe enough to fail, the core substance of Sacks’s prediction—that in the days and weeks after SVB’s collapse, depositor flight would spread to other regional banks, causing significant cash outflows and runs at multiple institutions—is borne out by subsequent events.

Therefore the prediction is right.