Bank delays PayPal deposits when I have a low cash balance. Is this legal? (MA)

Laws governing ACH transfers are complicated, but NACHA Operating Rules & Guidelines generally require that banks settle ACH transfers within two business days of receipt (i.e., your bank's receipt) from the clearinghouse. You have to add to that the processing time for PayPal to initiate the transfer, and for the clearinghouse to process it, so generally up to two days before that (although that may get shorter in the future). As long as they are within those guidelines, they are good. If there is a violation of the NACHA rules, your bank or Paypal can report it but you as a consumer cannot. There are fines for violations.

Also, under Dodd-Frank, it is unlawful for any provider of consumer financial products or services or a service provider to engage in "any unfair, deceptive or abusive act or practice." That's incredibly broad. The standard for unfairness in the Dodd-Frank Act is that an act or practice is unfair when:
(1) It causes or is likely to cause substantial injury to consumers;
(2) The injury is not reasonably avoidable by consumers; and
(3) The injury is not outweighed by countervailing benefits to consumers or to competition.
If they are truly making a distinction purely based on balance, this might qualify. You could make a CFPB complaint here

/r/legaladvice Thread