A donor’s lucrative retention plan and six-figure salary increases could help keep Arizona’s top athletics employees around for a long time.

An unnamed UA benefactor has offered to donate $17.68 million worth of stock that could result in multimillion dollar retention bonuses for athletic director Greg Byrne, basketball coach Sean Miller and football coach Rich Rodriguez, according to records for next week’s Arizona Board of Regents meeting.

The Regents are scheduled to vote on the proposal next week, along with contract extensions through 2019 and raises for all three of the high-profile UA employees.

The donor’s plan would offer Byrne 20 percent of the stock (a current value of about $3.5 million), while Miller and Rodriguez would get 35 percent ($6.19 million) each if they meet the retention criteria: Each needs to stay at UA at least four years and cannot leave voluntarily before eight years.

Byrne declined to comment, pending the Regents’ review of the proposal, and UA president Ann Weaver Hart were unavailable for comment Wednesday. But Regents chair Rick Myers said he believed the donation will be in the form of company stock that would be donated to the University of Arizona Foundation.

“It’s not cash,” Myers said. “There are horror stories out there of boosters at universities who try to put something in place. … This is all transparent, and the money flows through the university. The university maintains control so there are no side deals.”

Miller and Rodriguez already have smaller cash incentives to stay at UA: Miller would receive a $2.1 million retention bonus if he stays through 2015-16, and Rodriguez would receive $500,000 if he stays through November 2016.

Under the proposed donor’s plan, 90 percent of the stock allocated for the three employees would be managed by Barclays for the eight years, with quarterly distributions of income to be spent by the athletic director.

In addition, the other 10 percent of the stock would be held for the university, and its distributions would be controlled by the UA president.

The proposal says a total of 500,000 shares with a value of $35.36 each as of May 12 (a total of $17.68 million) would be donated.

At that value, Byrne would receive a bonus of $3.536 million, and Miller and Rodriguez would each earn $6.188 million if they met the retention criteria. At the end of eight years, the three could keep the stock or sell it.

If any of the three leave voluntarily before eight years, they would forfeit their shares, which will be given to the athletic director to use as needed in consultation with the donor, according to Board of Regent records.

But if UA decides to fire any of them without cause before the eight years are up, they would still collect.

If they are terminated without cause in their first four years they would receive a prorated amount — for example, a three-eighths share if fired after three years — and if they are terminated without cause after their fourth year they would receive the entire amount.

The plan is unusual in athletics, though Myers said other departments of the university have received similarly structured gifts.

“This shows we’re lucky to have some great people and a wonderful individual who is willing to recognize that,” Myers said. “To me, it’s positive from all angles.”

Meanwhile, the Board will vote on proposed raises to

Byrne, Miller and Rodriguez, and extensions for all three through 2018-19.

Byrne’s base salary would jump from $500,000 to $625,000 as of June 1, and it would increase another $25,000 every year through June 2018.

Miller’s contract would be extended one year to 2018-19, and his base salary, which had $100,000 annual escalators through 2016-17 but will not increase in 2017-18, would receive another $100,000 in 2018-19. He would receive a total package of $2.7 million plus incentives in 2018-19.

Rodriguez’s base salary of $1.33 million would be increased to $1.5 million as of June 1 and would rise by another $100,000 every year through June 2018. Rodriguez earned a total of $2.15 million last season.

Sportswriter for the Arizona Daily Star covering Arizona Wildcats basketball