(Recasts, adds Air France-KLM placement)
FRANKFURT, April 13 (Reuters) - An investor has sold shares in Lufthansa and Air France-KLM, a source familiar with the transaction said on Thursday, taking advantage of recent gains in the airlines' share prices.
Infinite Miles placed a 2.5 percent Lufthansa stake at 15.25 euros ($16.26) apiece, while it sold a roughly 3.5 percent stake Air France-KLM stake at 7.30 euros apiece, the person said.
The source described Infinite Miles as a financial investor rather than as a strategic or institutional shareholder. Other media reports said Infinite Miles had invested in the two carriers only in the fourth quarter of 2016.
The placement hit shares in the two carriers on Thursday, with Lufthansa down 3.75 percent at 15.09 euros and Air France-KLM down 5 percent to 7.12 euros by 0850 GMT.
There was no immediate comment from Lufthansa and Air France-KLM.
Shares in the two carriers have performed strongly this year, with Lufthansa up almost 28 percent and Air France-KLM gaining 45 percent, far outperforming other major European airlines thanks to progress on cost cuts and more positive comments on ticket prices.
After years of falling ticket prices putting yields under pressure, both Lufthansa and Air France-KLM made more upbeat comments on pricing this week, boosting their shares further.
UBS acted as bookrunner in both transactions. ($1 = 0.9376 euros) (Reporting by Arno Schuetze; Writing by Victoria Bryan; Editing by Ludwig Burger/Keith Weir)