It is possible for an influent (private) agent, namely someone who has the power to direct the market, to buy a stock before giving a positive announcement about the stock itself? Does his investment need to be public so that other investors can understand that his move can be just a manipulation of stock's value? Will it be considered insider trading? How often does this happen?

What I think is that a behaviour like this if reiterated will become not credible so it should be avoided because you can just lose your credibility and that could damage you more than what you obtained, always if the investment is public.

However, if you manage to influence the value for a good amount of time then changing your mind maybe will not make people think you're playing with the market. Is this correct?

It is possible for an influent (private) agent, namely someone who has the power to direct the market, to buy a stock before giving a positive announcement about the stock itself? Does his investment need to be public so that other investors can understand that his move can be just a manipulation of stock's value? Will it be considered insider trading? How often does this happen?

What I think is that a behaviour like this if reiterated will become not credible so it should be avoided because you can just lose your credibility and that could damage you more than what you obtained, always if the investment is public.

However, if you manage to influence the value for a good amount of time then changing your mind maybe will not make people think you're playing with the market.

It is possible for an influent (private) agent, namely someone who has the power to direct the market, to buy a stock before giving a positive announcement about the stock itself? Does his investment need to be public so that other investors can understand that his move can be just a manipulation of stock's value? Will it be considered insider trading? How often does this happen?

What I think is that a behaviour like this if reiterated will become not credible so it should be avoided because you can just lose your credibility and that could damage you more than what you obtained. Yet, if you manage to influence the value for a good amount of time then changing your mind maybe will not make people think you're playing with the market. Is this correct?

Cross posted on economics stackexchange.

It is possible for an influent (private) agent, namely someone who has the power to direct the market, to buy a stock before giving a positive announcement about the stock itself? Does his investment need to be public so that other investors can understand that his move can be just a manipulation of stock's value? Will it be considered insider trading? How often does this happen?

What I think is that a behaviour like this if reiterated will become not credible so it should be avoided because you can just lose your credibility and that could damage you more than what you obtained, always if the investment is public.

However, if you manage to influence the value for a good amount of time then changing your mind maybe will not make people think you're playing with the market. Is this correct?