we all know existing option series sometimes get adjusted after a corporate action (f.e. stock split, special dividend etc). sometimes the exercise price or multiplier is adjusted, sometimes a new series is introduced.
for example, DUK had a stock split not so long ago. The existing series became DUK1, the newly introduced series DUK. usually almost all existing liquidity goes to the new series, and the old ones become very illiquid.
anyway, Interactive Brokers doesn't let you trade the adjusted series; you are only allowed to close out your existing position.
Now over to my question: are there any brokers that do allow opening up positions in adjusted series? or do all brokers only offer them as a close-only?