Jamilah Fraser, the district's chief communications officer, confirmed the $1.5 million estimate but stressed that Ackerman had no plans to leave the district and its 154,482 students.
"Unless the powers that be decide that her services are no longer needed at the district, she intends, and wants, to remain in the position, fighting to ensure that all students receive a high-quality education," Fraser said in a statement.
When former schools chief Paul Vallas left in June 2007, he collected $180,000 in unused vacation and sick time, deferred salary, and retention pay.
Late last month, Ackerman dismissed rumors that she was leaving. At that time, she acknowledged signing documents delegating authority to sign district documents to Deputy Superintendent Leroy Nunery during July and August. But she said it was routine paperwork, recommended by attorneys for while she is on vacation.
State Rep. Michael McGeehan, one of Ackerman's most vocal critics, Friday called on Mayor Nutter and Gov. Corbett to oppose a buyout. Giving her money to leave, he said, would not only amount to handing her a golden parachute but a "pure platinum one."
He said the superintendent has so "woefully mismanaged" the district that she should be fired for cause.
McGeehan cited several issues in Ackerman's three-year tenure, including questionable procurement practices, a federal report criticizing the district's handling of racial violence at South Philadelphia High School, a $629 million budget shortfall, and an expanding probe into possible cheating on state PSSA tests.
McGeehan, a Democrat from the Northeast, said members of his staff met with Corbett's aides Friday and hand-delivered his letter.
Ackerman's contract states that if she is to be terminated for cause, the SRC must give her three months' written notice unless she is alleged to have committed a felony. She would be entitled to benefits due on her termination date but would not be entitled to anything further.
If Ackerman elected to step down, her contract says she must give the SRC 90 days' notice and forgo further salaries and benefits.
Ackerman is paid a base salary of $348,140 under the five-year contract she signed in 2008. She received an automatic one-year extension to 2014 in March when neither she nor the SRC signaled an intention to end the agreement.
At that time, Shana Kemp, a district spokeswoman, pointed out the SRC had adopted "Imagine 2014," Ackerman's five-year reform plan.
The one-year extension, Kemp said, would enable Ackerman to lead the district through the full implementation of the initiative.
"The SRC believes that stability in the leadership of the district during the full implementation of the plan is highly desirable," Kemp said then.
A small band of Ackerman supporters held a rally Friday to decry efforts to oust her.
"We've heard that there is a move afoot to remove Dr. Ackerman, that they will discontinue all of the 2011-12 Promise Academies, so we had to act," said Pamela Williams, organizer of the gathering, which drew about 15 people.
Promise Academies are district-run turnaround schools that receive extra money. There were six in the 2010-11 school year; 11 more are planned for September. The schools are part of Imagine 2014.
The rally was to have been held outside district headquarters at 440 N. Broad St., but the intense heat moved the gathering to the atrium inside the building.
Williams, a school police officer, spoke for 20 minutes about the problems of education and how Ackerman is trying to solve them.
"We stand here today to say, give her the opportunity to work through her Imagine 2014 initiative," said Williams.
Williams blamed the low attendance on the heat, and said another rally was scheduled for Tuesday at City Hall.
"Don't think because I have this little bit of people behind me, that there isn't a force of parents and civic leaders and people who care about the children in the city of Philadelphia," Williams said.
A district source said the posters at the rally were made by the district's communications office. "That's not correct," Kemp said. "The posters were not prepared by us."
Contact staff writer Martha Woodall at 215-854-2789 or firstname.lastname@example.org.