Nearly two dozen companies, including some of the biggest employers in Massachusetts, have pledged to step up enforcement and monitoring of their employees buying sex on company time.

“Sex buyers often look to buy during business hours, using company equipment and computers,” said Attorney General Maura Healey, speaking at a press conference yesterday. “In the Boston area, at this very hour, this is the peak time to purchase online sex, right in the middle of the workday.”

Healey and Mayor Martin J. Walsh announced a new coalition of businesses aimed at preventing sex trafficking. The initiative, called Employers Against Sex Trafficking, tries to impact sex trafficking by targeting customers.

The group is made up of 23 companies, including Partners HealthCare, IBM and Google. The companies have agreed to implement zero-tolerance policies for employees who buy sex.

Bob Rivers, chief executive of Eastern Bank, another company participating, said he plans to tell employees today the company can and will start monitoring internet activity related to buying sex.

“We have this policy and reminding them, but also letting them know that we do have the capabilities to monitor their computer activity, and we will,” Rivers said. “The capabilities do exist to monitor your activity with respect to these sites. You will get caught. Ultimately, that threat and delivering on that threat will be a very, very strong deterrent.”

Research from Demand Abolition, a advocacy group, found the common time for searches for sex buying is 2 p.m. Demand Abolition has said nearly a quarter of sex buyers have said they bought sex while on business trips, while nearly 13 percent of calls to decoy ads came directly from businesses.

Last year, Healey and Walsh both put zero-tolerance policies in place in their offices. Healey said law enforcement, including her office, will continue to target sex traffickers, but said targeting demand of sex will go a long way toward reducing the number of victims.