https://www.schwab.com/pricing1. Standard online $0 commission does not apply to over-the-counter (OTC) equities, transaction-fee mutual funds, futures, fixed-income investments, or trades placed directly on a foreign exchange or in the Canadian market. Options trades will be subject to the standard $0.65 per-contract fee. Service charges apply for trades placed through a broker ($25) or by automated phone ($5). Exchange process, ADR, and Stock Borrow fees still apply. See the Charles Schwab Pricing Guide for Individual Investors for full fee and commission schedules.
Above Footnote1 refers to this Guide that mentions $6.95 commission for OTC stocks.,
https://www.schwab.com/legal/schwab-pricing-guide-for-individual-investors