Starting in 2018, clients who purchase a derivative instrument such as a long call having a delta below the .80 threshold and sell a put on the same underlying and same share quantity within 2 days of one another will have those positions combined for the purpose of determining whether the threshold has been exceeded (e.g., the purchase of a long call with a delta of 0.60 coupled with the sale of a put with a delta of .40 would result in a long delta of 1.0).
In 2017, only over-the-counter instruments are potentially subject to combination to create a delta 1.0 instrument.