HERE’S something that the struggling hotel sector prefers not to spotlight: it is a favorite target of hackers.

A study released this year by SpiderLabs, a part of the data-security consulting company Trustwave, found that 38 percent of the credit card hacking cases last year involved the hotel industry. The sector was well ahead of the financial services industry (19 percent), retailing (14.2 percent), and restaurants and bars (13 percent).

Why hotels? Well, to paraphrase the bank robber Willie Sutton, hackers hit hotels because that is where the richest vein of personal credit card data is. At hotels with inadequate data security, “the greatest amount of credit card information can be obtained using the most simplified methods,” said Anthony C. Roman, a private security investigator with extensive experience in the hotel industry.

“It doesn’t require brilliance on the part of the hacker,” Mr. Roman said. “Most of the chronic security breaches in the hotel industry are the result of a failure to equip, or to properly store or transmit, this kind of data, and that starts with the point-of-sale credit card swiping systems.”