Tell that to the insiders who continue with their planned sales.
You seem to be suggesting that management should cancel 10b-5 trading plans when they think the stock is undervalued. Perhaps that was lawful but it was always controversial and it now appears even more dubious, at least according to this discussion in Wikepedia:
A possible loophole: canceling plans
After Rule 10b5-1 was enacted, the SEC staff publicly took the position that canceling a planned trade made under the safe harbor does not constitute insider trading, even if the person was aware of the inside information when canceling the trade. The SEC stated that, despite the fact that 10b5-1(c) requires trades to be irrevocable, there can be no liability for insider trading under Rule 10b-5 without an actual securities transaction, based on the U.S. Supreme Court's holding in Blue Chip Stamps v. Manor Drug Stores, 421 U.S. 723 (1975).
This staff interpretation raises the possibility that executives can exploit this safe harbor by entering into 10b5-1 trading plans before they have inside information while retaining the option to later cancel those plans based on inside information. Although paragraph (c)(1)(i)(C) does deny the affirmative defense to offsetting or hedged transactions, in that case there would still be an actual trade (whichever of the offsetting trades was not canceled) that could constitute insider trading and violate Rule 10b-5. The SEC's position is that there can be no insider trading without a trade, so that a person could cancel a planned trade based on inside information and avoid liability. Although technically any plan that is cancelable does not come under the 10b5-1 safe harbor, proving that an executed trade was hypothetically cancelable might be very difficult.
A few academic commentators have written about this issue, arguing that insiders can make systematically above-market profits by using 10b5-1 plans that they are still able to cancel. One empirical study has found that insiders using 10b5-1 plans do in fact make above-market profits (the paper also alludes to other potential loopholes that might explain this result), and another has found that the presence of publicly-announced 10b5-1 plans has economic effects on securities markets that are generally associated with insider trading. Others contend that rather than timing trades, executives may time news or press releases to move the stock before a 10b5-1 plan sale.
[edit] SEC reaction
Noted in a speech by Linda Chatman Thomsen, the SEC chief enforcement officer, the SEC is now investigating why 10b5-1 trades appear to outperform the market. Allegations of improper 10b5-1 trades were noted during the insider trading trial of Joseph Nacchio, former Qwest CEO. There are also preliminary investigations into 10b5-1 trades by Angelo Mozilo, from Countrywide. The SEC sent a Wells Notice to Mozilo in May 2009, suggesting intent to pursue civil charges in relation to alleged illegal trade through his 10b5-1 plan.
On March 25, 2009, the SEC staff revised its interpretative guidance regarding the circumstances under which the affirmative defense in Rule 10b5-1(c) is available. In particular, the staff followed the approach previously urged by some commentators to clarify (1) that the cancellation of a 10b5-1 plan could call the good faith of other, executed plans into doubt and (2) that the Supreme Court's decision in Blue Chip Stamps v. Manor Drug Stores, 421 U.S. 723 (1975), did not affect the SEC's ability to bring an enforcement action against a would-be insider trader who canceled a trading plan and did not trade in a particular transaction because a subsequent decision, Merrill Lynch, Pierce, Fenner & Smith, Inc., v. Dabit, 547 U.S. 71 (2006), made clear that Blue Chip Stamps dealt only with the implied private right of action for violations of Rule 10b-5 and not the "in connection with" requirement for all Rule 10b-5 violations.
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