No, they can't. They can't use customer funds for DTCC deposit requirements. It's just not allowed.
IIRC the deposit requirement was raised to 100%.
Even if the customer funds were settled, and the customer wanted to buy 1 share of GME for $300, Robinhood would have to post $300 of it's own money, just in case. Now would Robinhood get that money back? Most likely, but that doesn't mean they don't have to have it to deposit in the first place.
Hrm, so that makes Robinhood's situation even more impossible then. There's nothing they could've done to continue to allow people to buy $GME absent coming up with billions of dollars for a few days' worth of deposits.
the question becomes - who/what had the power to raise this deposit ratio, and did parties that would stand to lose a lot if GME continued to rise had influence in making this deposit requirement higher?
The DTCC raised the requirement, and my understanding is that these requirements are generated formulaically; not publicly available, but is based on volume, volatility, etc of the individual underlying assets, and how exposed specific institutions are to that volatility.
The DTCC wouldn't care one way or another if GME went up or down. They're goal is to make sure that different parties are able to settle their obligations with a very high degree of certainty, and ensure that investors won't lose their money with solvent brokerage firms or other intermediaries.
If you're arguing that the DTCC is beholden to the whims of a (relatively) miniscule hedge fund, you're crossing into conspiracy theory territory.
IIRC the deposit requirement was raised to 100%.
Even if the customer funds were settled, and the customer wanted to buy 1 share of GME for $300, Robinhood would have to post $300 of it's own money, just in case. Now would Robinhood get that money back? Most likely, but that doesn't mean they don't have to have it to deposit in the first place.