Open-market manipulation

Open-market manipulation is manipulation carried out through transactions that are, individually, entirely ordinary and lawful. Courts have divided on whether trades that are facially legitimate can be manipulative purely by reason of intent, and the doctrinal question remains unsettled.

history and doctrine · updated 2026-09-08

Where does open-market manipulation come up?

This term is used in the following manipulation techniques, each explained in full on its own page.

Marking the close — Marking the close is trading in the final minutes of a session specifically to move the closing price, which is the price that sets portfolio valuations, margin calls, index levels and derivative settlements.
Momentum ignition — Momentum ignition is entering a burst of aggressive orders designed to trigger other participants' momentum strategies, creating a price move the initiator then trades against.

Enforcement actions involving these techniques

Action	Agency	Filed	Technique	Penalty	Status
SEC v. Canaccord Genuity LLC (marking the close, 2026)	SEC	2026-03-06	Marking The Close , Marking The Open +2	—	settled
SEC v. Ahmad Haris Tajyar and Eric Leo Marsoubian (marking the close, 2021)	SEC	2021-08-13	Marking The Close , Matched Orders +1	$220k	settled
SEC v. Andrew J. Kandelapas (marking the close, 2019)	SEC	2019-06-21	Marking The Close	—	judgment
SEC v. Lai Guanglin (Alan) (marking the close, 2018)	SEC	2018-12-10	Marking The Close , Price Manipulation	—	settled
SEC v. Richard P. Cedrone, Steven R. Ferris and George R. Thoreson (marking the close, 2017)	SEC	2017-09-05	Marking The Close	$75k	judgment

Open-market manipulation

Where does open-market manipulation come up?

Enforcement actions involving these techniques

See also