NEW YORK — PetSmart said Wednesday that it has been taken private, as a group of investors led by the buyout firm BC Partners completed their $8.7 billion acquisition.

PetSmart President and CEO David Lenhart and Chairman Gregory Josefowicz are stepping down as part of the deal. Michael Massey is being named president and CEO, and Raymond Svider is the new nonexecutive chairman. Massey is the former CEO of Collective Brands Inc., which owns Payless ShoeSource, and Svider is managing partner at BC Partners.

Lenhart became CEO of PetSmart in June 2013, the same time Josefowicz became chairman. Lenhart became president of the company in April 2014.

In early July the activist hedge fund manager Jana Capital disclosed that it had taken a stake in PetSmart and had become the Phoenix-based company’s largest shareholder. Jana Partners said it wanted to talk to PetSmart’s board about a possible sale of the company and other changes that it said would improve company performance. Another major shareholder, Longview Asset Management, also pushed for the sale.

PetSmart Inc. shareholders approved the sale Friday. The company has 1,387 stores in the U.S., Canada and Puerto Rico.