PORTLAND – Nearly $18.8 million have been paid out in lump-sum payments to five top executives at TD Banknorth from a long-term incentive plan triggered by the bank’s sale earlier this year.

The incentive plan called for accelerated payouts in case of change in ownership, which occurred this winter when TD Bank Group of Toronto bought 51 percent of Portland-based Banknorth in a deal valued at $4 billion.

The payouts, which were made last year and detailed in a Securities and Exchange Commission filing this week, are in addition to another $36 million in executive compensation linked to the bank sale that was disclosed last year.

William J. Ryan, Banknorth’s president and chief executive officer, received the biggest chunk of the new payments, drawing nearly $6.3 million from the long-term incentive plan. Four other top executives each were paid more than $3.1 million from the plan.

Change-of-control provisions within employment contracts and incentive plans are common for top executives at many companies. The promise of payouts help retain executives who might otherwise jump ship if a sale is in the works and if they worry that their jobs may be eliminated after the transaction.

In the case of Banknorth and TD Bank, the sale was accomplished with the executive team intact.

With the sale pending last fall, Banknorth reached new employment contracts with its top executives in which they agreed to forgo immediate change-in-control payments that would have paid them millions more when the deal was complete. Instead, the new contracts have retention incentives that will provide them with millions more in stock and cash after three years with TD Banknorth.

Under those agreements, Ryan will receive an additional $12 million in cash and stock in three years. Peter Verrill, the chief operating officer, will receive about $6 million, and six other top executives will get $3 million each.

Jim Ackor, a banking analyst with RBC Capital Markets, said the dollar amounts sound huge, but aren’t out of the ordinary for the industry and for top executives at large companies.

“Obviously, it’s a lot of money when you add it up,” Ackor said, but “it’s certainly not out of whack.”

Ackor noted that Ryan has helped build Banknorth into a large, well-run bank. It was 33rd nationally in terms of revenue in a ranking of the top commercial banks released this week by Fortune magazine.

It hasn’t been just top executives who have profited from the deal with TD Bank.

Company spokesman Jeff Nathanson said employees have exercised stock options on approximately 8 million shares since last August. An option allows someone to purchase stock at a predetermined price, even if that company’s stock is selling for more money on the open market. The price difference creates an immediate profit for the individual exercising an option.

Collectively, the exercise of these options netted Banknorth workers tens of millions of dollars.