Brookdale Senior Living, which owns and operates hundreds of assisted living facilities, is still facing pressure from an activist investor despite ousting its CEO this month.

Tennessee-based Brookdale, one of the largest operators of retirement communities, parted ways with former CEO Lucinda Baier on April 13 amid pressure from activist shareholder Ortelius Advisors, led by CEO and co-founder Peter DeSorcy.

But in a letter to Brookdale's stockholders Thursday, DeSorcy called for Brookdale to break up its portfolio by selling properties and exiting leases to reverse what it called a “massive destruction of stockholder value.”

Brookdale owns 353 properties and leases another 266, catering to roughly 58,000 residents across 41 states.

Ortelius says about 66% of Brookdale's communities have occupancy above 75%, while the remaining 34% — more than 200 properties — are below that threshold. It's those underperforming stores that Ortelius says Brookdale should sell off to pay down its debt.

Ortelius began its activist campaign last month when it nominated six new directors to the company's board, citing a 39% stock price decline over the last seven years. About a month later, Brookdale announced Baier's departure, along with that of another board member.

The activist reiterated on Thursday its call for Brookdale's shareholders to vote in its alternative slate of directors.

“After years of missteps and shortcomings, stockholders have lost confidence in the incumbent Board’s decision-making abilities, and the Board cannot be trusted to take decisive action, necessary after the vast destruction of stockholder value, and put stockholders first,” Ortelius letter reads.

A spokesperson for Brookdale didn't respond to a request for comment.

Brookdale Chairman Denise Warren has taken the mantle of interim CEO, and Ryman Hospitality Properties CEO Mark Fioravanti has filled Baier’s board seat, according to the filing.

On Thursday, Onex Managing Director Joshua Hausman was appointed as an independent director, according to a release.

"The continuing refreshment of our board with highly qualified directors reflects our commitment to bringing in new expertise and perspectives and follows engagement with our shareholders,” Warren said in a statement.

Baier took over as CEO in 2018 and implemented a vast reduction in Brookdale's portfolio — it had 1,100 properties at the time, Senior Housing News reported. She spent years renegotiating its leases with major landlords Ventas and LTC Properties and converted properties from leased to owned.

Ortelius owns 1.3% of Brookdale's stock, SHN reported.