The website of Vanguard Group is showing "inflated client account balances" on some mobile devices, a spokeswoman for the index fund manager said via e-mail on Monday. The issue "does not impact actual account balances or transactions," said the spokeswoman, Katie Henderson Hirt, and is "relegated to Apple devices only." Vanguard expects to have the issue fixed on Monday evening, she added. Asked how many devices were affected, Hirt said the impact was a "modest number overall." On average just 16 percent of logons to vanguard.com come from an Apple device, she said, and of those about 11 percent visit the personal performance page where they would have seen the inflated balance.