The European Union fined Microsoft Corp. a record $1.3 billion Wednesday for the amount it charges rivals for software information.

EU regulators said the company charged “unreasonable prices” until last October to software developers who wanted to make products compatible with the Windows desktop operating system.

The fine is the largest ever for a single company and brings to just under $2.5 billion the amount the EU has demanded Microsoft pay in a long-running antitrust dispute.