Schwab does have a 6% minimum cash allocation which afaict they pay ~0.15% on. If you could have invested that at 10% nominal returns you're paying 0.591% in opportunity costs.

the fees are tucked into their allocation strategy. they hold no less than 7% in cash for all strategies. They claim it smooths out returns but it's not desirable and can limit returns https://thefinancebuff.com/schwab-intelligent-portfolios-hol...