For more than a year the public has been waiting for the outcome of the watchdog's investigation.

Yingluck, a sister of ousted prime minister Thaksin Shinawatra, was AIS president and a large Shin Corp shareholder. AIS is a profitable Shin Corp subsidiary.

Between October 2005 and January 2006 Yingluck sold 370,000 AIS shares at an average price of Bt105 each. This occurred before January 23, 2006 when she sold her Shin Corp stake to Temasek Holdings of Singapore - along with other Shinawatra and Damapong family members.

Did Yingluck benefit from inside information? She did unload her substantial AIS holdings well ahead of the Shin Corp transaction.

The SEC's year-long probe concluded there was no evidence to suggest Yingluck relied on inside information.

The SEC said Yingluck, as AIS president, held no management position at Shin Corp. She sold AIS shares received from employee stock options. Many companies offer shares to executives and employees as incentives. The SEC added Yingluck sold her options immediately after every receipt since 2003.

The SEC statement is almost word-for-word the argument Yingluck used in her defence.

The SEC judgement could set a precedent for any company director or executive to sell options, although in some cases they might do so using inside information.

 Yingluck argued she was unaware of the pending negotiations between Shin Corp, Temasek and other Shinawatra and Damapong family members. If she was indeed unaware, or was not informed about the deal, why would she, too, offload her Shin Corp holdings together with her relatives on the morning of January 23, 2006?

Temasek bought 49 per cent of Shin Corp from the Shinawatra and Damapong families for Bt49.25 a share, or a total of Bt73.3 billion.

An argument can be made insider trading was involved. It is public knowledge that on July 1, 2005 a Shinawatra family representative wrote to the Revenue Department to inquire if the prime minister's son Panthongtae would incur tax liability if he purchased Shin Corp stock from Ample Rich at Bt1 a share.

This was written before Yingluck sold her AIS stocks between October 2005 and January 2006. On January 23, 2006 Temasek made a tender offer for all AIS stock at Bt72.31 a share - significantly below the then trading price and even less than Bt113, the highest Yingluck sold at.

Minority shareholders were entitled to ask questions. Since she was about to pocket Bt982 million from selling 20 million Shin Corp shares to Temasek, why did she not hold on to her AIS stock?

While she was selling AIS paper minority shareholders were in the dark. They suffered by being forced to sell to Temasek at a steep discount.

If AIS told the public about the pending deal its shareholders would have been given an equal chance to sell in advance of its closing.

Those who benefited must have known AIS would fall after any tender offer.

Insider trading laws exist to protect small shareholders and to prevent big stakeholders or management taking advantage of information only they are privy to.

In this instance the SEC has failed the public.

(Ma Nok [Alien Horse] and Dek Nok Krob [Outside-the-Box Kid] are pseudonyms for the co-authors of "25 Questions: A Behind-the-Scenes Look at Shin Corp Takeover".)

Ma Nok and Dek Nok Krob

Special to The Nation