Sen. Ted Cruz had his costliest month of the presidential campaign in February, spending $17.5 million as he battled front-runner Donald Trump through a series of GOP primary contests, an effort that ran down his cash reserves.

Cruz campaign manager Jeff Roe wrote in a tweet that the senator from Texas raised $11.9 million last month, up from the $7.6 million his campaign collected in January. But Cruz entered March with just $8 million in the bank, down from the $13.6 million he had at the beginning of February.