Closed period
M&A / Merger ModelA defined window before an issuer announces results in which its directors and senior managers may not deal in its shares, whether or not they hold inside information.
Also written: close period, closed periods, blackout period
Under the European market abuse regime a person discharging managerial responsibilities, broadly a director or a senior manager with access to inside information and the power to take decisions about the issuer's development, may not deal in the issuer's shares or debt instruments during a defined period before the announcement of its results.
The rule is deliberately blunt. It does not ask whether the individual actually held inside information at the moment of the trade, because that test would be unworkable to police and impossible to verify. A flat prohibition over a fixed window is easier to obey and easier to enforce, and the cost of occasionally catching an innocent trade is accepted.
It is not the rule that binds a junior in a bank. Your constraint comes from your firm's personal account dealing policy, which is generally stricter: pre clearance of every trade, dealing through approved channels, a minimum holding period, limits on short term trading, and application to accounts you do not own but influence, typically a spouse's and dependants'.
Pre clearance requests are refused without explanation, and the reason for that is worth understanding rather than resenting. Telling you why a name is blocked would itself disclose that the firm has something live on that name, which is exactly the information the whole apparatus exists to contain.
Worked example
A finance director wants to sell shares three weeks before the full year results. The closed period bars it even though she has seen nothing that is not already public, because the window rather than her knowledge governs.
An analyst wants to buy shares in a company nobody on her team has ever mentioned. The request is refused with no reason given, because the firm is on the other side of a matter in that name.
The refusal without a reason is not obstruction. Explaining it would be the leak.