Shares of MoneyGram International Inc. shot up 38 percent in after-hours trading Tuesday after a report that the money transfer company is in early stage talks to be acquired by larger rival Western Union Co.

The report, by Bloomberg News, cited anonymous sources with knowledge of the matter. Talks may still fall apart, Bloomberg said.

MoneyGram has offices in St. Louis Park; it was based in the Twin Cities until moving its headquarters to Dallas in 2011.

Shares of MoneyGram, which has a market value of about $400 million as of ­Tuesday’s close, were trading at $10.74 late Tuesday after closing the regular trading day at $7.80.

MoneyGram had $963.5 million in long-term debt as of Dec. 31, according to its annual filing.

Western Union has a market value of about $11 billion.

One potential hurdle is whether regulators would block the deal on antitrust grounds, the Bloomberg report said.

A spokeswoman for MoneyGram said the company does not comment on rumors and speculation. Western Union could not be reached for comment.