News can be suppressed during confidential negotiations, but the way it's supposed to work is that news is filed with the regulators along with a notice that there is a confidentiality agreement in place, and that negotiations are underway. The regulators will immediately halt the issuer at the first sign that there has been a leak, based on trading price and volume, and force public release of the stalled news. I'm sure that the rules are not always followed, however.

Lar

Here's the whole blurb (and that's a link) from the TSX-V Timely Disclosure Policy 3.3

11. Confidential Information
11.1 In isolated and restricted circumstances, and in accordance with applicable Securities Laws, disclosure of Material Information concerning the business and affairs of an Issuer may be delayed and kept confidential temporarily if immediate release of the information would be unduly detrimental to the interests of the Issuer.
11.2 The following are examples of certain instances in which disclosure may be unduly detrimental to the Issuer’s interests:
(a) release of the information would prejudice the ability of the Issuer to pursue specific and limited objectives or to complete a transaction or series of transactions that are under way. For example, premature disclosure of the fact that an Issuer intends to purchase a significant asset may increase the cost of making the acquisition;
(b) disclosure of the information would provide competitors with confidential corporate information that would be of significant benefit to them. Such information may be kept confidential if the Issuer is of the opinion that the detriment to it resulting from disclosure would outweigh the detriment to the market in not having access to the information. A decision to release a new product, or details on the features of a new product, may be withheld for competitive reasons. Such information should not be withheld if it is available to competitors from other sources; or
(c) disclosure of information concerning the status of ongoing negotiations would prejudice the successful completion of those negotiations. It is unnecessary to make a series of announcements concerning the status of negotiations with another party concerning a particular transaction. If it seems that the situation is going to stabilize within a short period, public disclosure may be delayed until a definitive announcement can be made. Disclosure should be made once “concrete information” is available, such as a final decision to proceed with the transaction or, at a later point in time, finalization of the terms of the transaction.
11.3 It is the policy of the Exchange that the withholding of Material Information on the basis that disclosure would be unduly detrimental to the Issuer must be infrequent and can only be justified where the potential harm to the Issuer or investors caused by immediate disclosure can reasonably be considered to outweigh the undesirable consequences of delaying disclosure. While recognizing that there must be a trade-off between the legitimate interest of an Issuer in maintaining confidentiality and the right of the investing public to disclosure of Material Information, the Exchange discourages any delays in disclosure for a lengthy period of time, since it is unlikely that confidentiality can be maintained beyond the short term.
11.4 Issuers that wish to keep Material Information confidential must also comply in all respects with relevant Securities Laws, which includes the filing of a confidential material change report with the applicable Securities Commission, if the Material Information constitutes a Material Change.
11.5 The Exchange requires copies of confidential material change reports filed by an Issuer with applicable Securities Commissions to also be filed with the Exchange and the Regulation Services Provider. The Exchange and the Regulation Services Provider must be advised of the Material Information on a confidential basis so that trading in the Issuer’s securities may be monitored by the Regulation Services Provider. If the trading of the Issuer’s securities suggests or indicates that the confidential information may have been “leaked”, the Regulation Services Provider will normally require the Issuer to disseminate a news release immediately. The Regulation Services Provider will halt trading in the Issuer’s securities until the information has been properly disseminated.
11.6 At any time when Material Information is being withheld from the public in accordance with this section, the Issuer must ensure that such Material Information is kept completely confidential and that persons in possession of such undisclosed Material Information are prohibited from purchasing or selling securities of the Issuer or “tipping” such information until the Material Information is publicly disclosed.
11.7 The Issuer has a duty to take precautions to keep such undisclosed Material Information confidential. Such information should not be disclosed to any officers or employees of the Issuer, or to the Issuer’s advisors, except in the necessary course of business. The directors, officers and employees of an Issuer should be reminded on a regular basis that confidential information obtained in the course of their duties must not be disclosed.
11.8 In the event that such confidential information, or rumours respecting the same, is divulged in any manner (other than in the course of ordinary business), the Issuer must make an immediate announcement of the Material Information. The Exchange and the Regulation Services Provider must be notified prior to the announcement in order that trading can be halted as described in section 11.5 above.
11.9 During the period before such Material Information is publicly disclosed, market activity in the Issuer’s securities will be closely monitored. Any unusual market activity suggesting that the undisclosed Material Information is being selectively disclosed or that persons are taking advantage of it will result in a halt in trading until the information has been properly disseminated.
11.10 Issuers should advise the Regulation Services Provider when they are working on potential material developments that may not be sufficiently advanced to require public disclosure and do not trigger the filing of confidential material change reports. In such circumstances, the Regulation Services Provider will generally closely monitor the Issuers’ securities for unusual trading patterns. When the Regulation Services Provider contacts an Issuer upon noting an unexplained change in the price or volume of the security the Issuer must disclose to the Regulation Services Provider the existence, nature and status of any potentially material development so that the Regulation Services Provider can monitor the market with that knowledge. If it appears that the news has leaked into the marketplace, the Regulation Services Provider will advise the Issuer and halt trading until the Issuer can make a suitable announcement.