Casper, the buzzy mattress seller adored by millennials, has a costly returns problem that could be a nightmare for its IPO

Casper, the online mattress vendor, is expected to go public as soon as this week.
But it has a costly problem that could dampen investor interest in its initial public offering — a generous return policy on its mattresses that is costing the company tens of millions of dollars a year.
In the first nine months of last year, returns, refunds, and discounts cost Casper $80 million — or about 20 cents of every dollar in sales it took in during that period. 
The company has also ha