Chase is running 30% a transfer bonus from Ultimate Rewards to British Airways, Iberia and Aer Lingus through December 9, 2020. Every 1000 Chase points becomes 1300 points in the destination program, and that bonus posts along with the transfer (usually immediately).
It’s only the annual fee Chase Ultimate Rewards cards (Sapphire Preferred/Reserve, Ink Business Preferred) whose points transfer to miles, though if you have other no annual cards and one or more of those you can transfer points from the no annual fee card to the one whose points transfer to miles and then take advantage of these offers.
Without a specific award in mind I’d be reluctant to do this. A 30% transfer bonus doesn’t offset the flexibility of using Chase points with whatever airline you wish later (or using the points to cover travel or other expenses directly). Although there are certainly places where you want to spend points with Iberia for instance because their transatlantic awards are really reasonably priced.
In October Chase ran a Southwest transfer bonus. In August Chase ran a transfer bonus to IHG. In Spring of 2019 they ran a transfer bonus to British Airways. That was their first transfer bonus ever. And now we’re back to the future two and a half years later.