I doubt it. In different accounts you do whatever you want. In the same account you can do it with a slight modification: long YM, short ES. Or long Sept YM and short Dec YM, supposed you are swingtrading...
I see some people just post to get their count up! It's probably a remedy for being unable to get anything else up.
This is not correct. A "wash sale", as defined by U.S. tax law, is the sale of a security within 30 days before or after the purchase of a substantially similar security. A "wash sale" is not illegal, though it does often receive a different tax treatment from other sales. A "wash trade", on the other hand, is a trade of shares in a security, in which the same party takes both sides of the trade. A "wash trade", if done with intent to deceive, violates the anti-manipulation provisions of the Securities Exchange Act of 1934. http://www.sec.gov/divisions/corpfin/34act/sect9.htm.
Self-dealing is one of the few regulations that appears to be strictly enforced by the futures exchanges.
Some of the swing traders like to do this. They will hold some contracts for days or weeks to catch bigger moves. Then they will have a second account that they do some daytrades with. So at times they will have longs and shorts open at the same time. Regards, 4re
Going "short against the box" is illegal with equities because it is a form of tax fraud. The long position in the box would be held for more than 6 months and so would get a more favourable tax status, but by shorting the stock in another account (or purchasing a put), you have effectively sold. You may also be trying to defer the sale into another year if it will place you in a better tax bracket. Because of the shorter terms on futures contracts, is this even an issue with futures?
Trading with illegal gains or laundered money. This would only come to someone's attention if your bank account and the size traded took a sudden huge spike, though.