Politico's Kasie Hunt reports: 

Rep. Mike Pence is expected to announce late Thursday whether he is running for president, POLITICO has learned. The announcement will appear first in the Indianapolis Star, an aide said.

I think it's now or never for a Pence presidential run, but that doesn't mean it's an easy decision. 

Update: the Indy Star reports that Pence will make his announcement in an interview with the paper after 7:00 p.m.