The phrase "acted collectively" is correct and usable in written English.
It can be used to describe a situation where a group of individuals or entities come together to perform an action or make a decision as a unified body.
Example: "The committee acted collectively to address the concerns raised by the community."
Alternatives: "worked together" or "joined forces".
If these funds acted collectively, they would have enormous investing power - and would be quite big enough to make significant investments in infrastructure.
The charges are part of an ongoing investigation into industry practices that suggest insurers and brokers have acted collectively (and secretly) to betray customers.
In each case, despite differing positions, the five have acted collectively to prevent advanced countries from driving wedges between them, said Sourabh Gupta of Samuels International Associates, an international trade and political risk assessment firm in Washington.
They reviewed the current bilateral agreements that cover the teams' payments and are in place until 2020 and, crucially, were involved with the Formula One Teams Association (Fota) – the last time they acted collectively and successfully, when in dispute with the FIA over regulation changes in 2009.
In the severe 1984 drought, the Chiredzi ICA acted collectively to save the few remaining sable in the area by capturing and feeding them (sable having been severely threatened by livestock overgrazing).
The men acted collectively during military actions.
Can we act collectively to resolve the problems which our collective life creates?
Another, "Collective Action and Advocacy," studies the way people act collectively to address social problems, a key component of sustainability, and examines environmental activism like the Greenpeace and Save the Whales campaigns.
We must act, collectively and urgently.
But we must act collectively and courageously.
Parties get self-interested people to act collectively.
