Aeroplan is offering some bonus miles for points transfers from their partner programs between May 21 and June 18, 2012. The bonus structure is as follows:

You can convert points from the following partners:

CIBC Aventura^®World MasterCard™ Card, CIBC Aventura^® Gold Visa™, CIBC Aventura^® Visa Infinite™, CIBC Aventura^® MasterCard™ Card, American Express Membership Rewards – Canada, BankAmericard^® Power Rewards^® credit card, Diners Club^® Club Rewards^®, Starwood Preferred Guest^®, Hilton HHonors™, Marriott Rewards, Wyndham Rewards^®, Best Western Rewards, Choice Privileges^®, Coast Rewards, Club Carlson^SM, Le Club Accorhotels (Accor hotels), Golden Circle Award, Hertz Gold Plus Rewards, Points.com

Please note that while Membership Rewards^® points from U.S. American Express Cardmember accounts may be converted into Aeroplan Miles, their conversion is not eligible for the bonus promotion.

As you can see, the US Membership Rewards program is excluded from the transfer bonus.

Looking at the above bonuses, if you transfer 100,000 SPG points to Aeroplan you would get a total of 150,000 Aeroplan miles (SPG gives you a 5,000 point bonus for every 20,000 points you transfer, plus the further 25,000 mile bonus).

Anyway, given that Aeroplan miles aren’t nearly as valuable as they used to be I wouldn’t just make a speculative transfer unless you have a specific redemption in mind where the numbers work in your favor.

Still, it’s a promotion worth keeping in mind.

(Tip of the hat to Gary)