Through February 28, Delta is offering a bonus on transfers from American Express Membership Rewards as follows:

Transfer Points	Mileage Bonus	Total Miles
1,000 to 49,000	10%	1,100 to 53,900
50,000 to 149,000	20%	60,000 to 178,800
150,000+	40%	210,000+

The bonus miles won’t post instantly the way that the initial transfer will, the terms and conditions say “Bonus miles will be posted two (2) weeks from the transfer receipt by Delta” although it’s possible the bonus miles will post more quickly than that.

Registration is required to earn the bonus.

Now, I’m not a fan of Skymiles in general. I would not be willing to give up the flexibility of Membership Rewards for a 10%, 20%, or 40% bonus just to park miles in Skymiles for the future (besides, transfer bonuses to Delta are quite common, though they’re usually less than 40%). But if you are looking to top off for a specific award, consider a modest transfer. And at 40% it would make Delta miles almost as valuable as the median currency in my estimation, though not quite.

Update: Frugal Travel Guy posted this offer as well, and comments “It takes some significant numbers to get to the 40% level (150,000 points), but heck, you need lots of DL miles to get anywhere anyway.”