Ben Carson called it quits on Friday, using a speech at the Conservative Political Action Conference to announce he was “leaving the campaign trail.” It was hardly a shock. He admitted to his supporters on Wednesday that he believed he had no chance at winning the Republican nomination, proved he meant it by skipping the Fox News debate on Thursday, and then went ahead and announced earlier in the day that he has already found his next job.

Carson proved ill-suited for the combative arena of modern politics. With the notable exception of a short stretch at the top of the national GOP polls last fall, he was often MIA during the campaign, including those times he literally left the trail to go on a book tour or go home to get a fresh set of clothes. Still, there was one thing Carson proved exceptionally good at as a politician: raising cash—and lots of it.

The former neurosurgeon brought in a staggering $57.9 million between the start of his campaign and the end of January—millions more than any of his Republican rivals. He raised about $3 million more that Ted Cruz, $23 million more than Marco Rubio, $32 million more than Donald Trump (admittedly a special case given his own personal fortune and promises to self-fund), and $49 million more than John Kasich. Carson’s fundraising machine was fueled by tons of small donors who cut checks of less than $200 to his campaign. According to Federal Election Commission filings, nearly three-quarters of his donations came in such small-dollar increments, a better percentage than any other candidate on either side of the aisle with the sole exception of Bernie “$27 Average Donation” Sanders.

But as impressive as Carson’s campaign haul appeared, a closer look at the numbers suggests that his team didn’t use it to build a campaign as much they used it to build a perpetual fundraising machine. Carson burned through roughly $54 million as of the end of January, nearly $13 million more than Cruz did and roughly the same amount as Rubio and Trump spent combined. As the Associated Press reported Friday, Carson gave at least a quarter of the money he raised to fundraising and marketing firms owned by two of his top consultants. Those firms, in turn, spent much of that money—minus their cuts, of course—on things like direct mail and digital outreach aimed at raising more money still.

What’s so remarkable about this type of campaigning for cash is that the donor lists that Carson’s team assembled will outlast even his own zombie candidacy. Other campaigns can rent the data from the Carson campaign and continue to solicit the donors indefinitely. As the Center for Public Integrity points out, Hillary Clinton’s 2008 campaign made more than $3.1 million renting its own lists in 2010, and Mitt Romney’s 2012 campaign made nearly $1.4 million doing the same thing in 2015.

Carson’s lists, meanwhile, are considered even more valuable on a per-donor basis than typical ones because so many of his backers were first-time donors, making them less likely to be on all those other lists already available for rent. By one estimate given to CPI, the Carson campaign could bring in upwards of $4 million over the next three years as a result. Not bad for 10 months of work.

Read more Slate coverage of the GOP primary.