From now until February 8, 2017, you can earn, effectively, a 33% bonus when you transfer Citi ThankYou points to Hilton HHonors points. For every 1,000 ThankYou points transferred, you will get 2,000 Hilton points, instead of the usual 1,500.
I’m glad Citi is running a bonus for Hilton points transfer, but to be honest, this is still a pretty poor value. I value Hilton points at around 0.4 to 0.5 cents apiece. It’s hard to value Hilton points at more than 0.5 cents each, especially since Hilton has sold points at that level before.
Meanwhile, I value Citi ThankYou points at least at 1.6 points apiece, since that’s how much they can be used on air travel on American Airlines (at least until July 2017). Even with this promotion, I am only getting about 1 cent per ThankYou point, which is terrible. Heck, I can redeem ThankYou points for retail gift cards at a higher level.
Still, if you need to top off your account for a free night, this could potentially be useful. Make sure you check whether Points and Money awards are available first, though.
Your other option would be to transfer American Express Membership Rewards points to Hilton. However, they currently have a rate of 1000 MR points to 1500 HHonors points, so it’s not as good of a deal (if a deal at all).