Exchange act rule 15c3-3 July 8, 2019 16 32 64 128 Exchange act rule 15c3 3 customer protection rule Securities exchange act rule 15c3 3 Rule 15c3 3 under the exchange act Exchange act rule 13a-15(d) Exchange act 15c3-3 Exchange act rule 15c3-1 Exchange act rule 15c3-5