UPDATED—"ROKU filed an 8-K saying that of its $1.9 billion of cash, $487mn is stuck at $SIVB (mostly UNINSURED)"

 They become an unsecured creditor.

Vikash Ruhil at Medium has the 8-K

There are going to be a lot of unsecured creditors. I think it was Reuters who reported that 85 - 90% of year-end 2022 deposits were over the $250K FDIC insurance limit.

That's over $150 billion uninsured. I shall make inquiries and update.

Update: It was indeed Reuters but I was off on the numbers. Here's the pertinent bit:

"....data submitted to the FDIC by the bank at the end of 2022 showed that 89% of its $175 billion in deposits were uninsured."

—"After Silicon Valley Bank's shutdown, uninsured depositors face tense wait"

Reuters via Yahoo Finance