But there are no other changes to the group's pay framework, despite concerns from one voting advisory group that the rewards of chief executive Martin Gilbert are "potentially excessive".
The group created by Mr Gilbert 30 years ago holds its annual meeting in Aberdeen today as Europe's biggest fund manager, in the wake of the blockbusting £650million acquisition of SWIP, its shares having quadrupled over the past five years to value it at £5.4billion.
Mr Gilbert was paid a £500,000 salary last year but his total rewards were worth £5.1m, a rise of 7% on the previous year. None of the four shareholder advisory groups are urging institutions to vote against the group's remuneration report but one, Pirc, says its followers should oppose AAM's remuneration policy.
Shareholder votes on remuneration reports are still only advisory, but on October 1 2013 business secretary Vince Cable gave shareholders the right to have a binding vote every three years on a company's overall remuneration policy. Aberdeen, with a year end of September 30, becomes one of the first companies affected.
AAM now says on its website that "following further discussions with shareholder representatives", executives appointed in future will normally be limited in contractual pay-offs to "base salary, pension and benefits for up to 12 months".
Shareholder group ISS says the change warrants support for the remuneration policy.
Pirc acknowledges that Mr Gilbert's pay has risen by 265% over the past five years, just below the 270% rise in total shareholder return. But it frowns on bonuses worth up to 13 times salary and says Mr Gilbert's bonus at 9.2 times salary is "potentially excessive"
The ABI, which gives AAM an 'amber top' report, says the potential for an uncapped bonus pool, albeit in "exceptional circumstances", is likely to make shareholders "sceptical".
A spokesman for AAM said: "As a leading investment company we welcome the introduction of the new voting arrangements." He added: "We are open and transparent in terms of our remuneration policy and report. We do not believe in rewarding failure and executive bonus awards take account of key financial performance indicators.
"Three-quarters of any bonus earned is paid in company shares and released in tranches over four years.