Fidelity Investments' Magellan mutual fund appeared to significantly boost its stake in Bank of America Corp. last month and added to its position in Goldman Sachs Group Inc., according to records released by the mutual fund giant.

The fund — a onetime industry bellwether that lost some luster last year as financial bets backfired — also boosted its holding in Wells Fargo & Co. during May, according to Fidelity's data.

The $22.4 billion-asset Magellan fund has gone back and forth with Bank of America in recent months. It significantly boosted its stake in the company last September, for example, then substantially reduced its holding a few months later.

But at the end of May, the market value of its stake in Bank of America was $398.6 million, making the company the 10th-largest holding in the fund. The stake's value is up more than eightfold from the amount reported for the end of April. The banking company's stock price rose 26.2% in May and has climbed further this month.

Goldman was already a big Magellan constituent at the end of April, when it was the portfolio's ninth-largest holding. Goldman moved up to the No. 6 spot in May as the market value climbed nearly 35%, to $475 million. Because the stock price rose only 12.5% during the month, the sharper rise in the Magellan position's market value indicates a beefed-up stake in the investment bank.

The value of Magellan's stake in Wells Fargo grew 80% in May, to $349.4 million, from April 30. The stock price rose 27.4% last month, also indicating a bigger position.

Subscribe Now

Access to authoritative analysis and perspective and our data-driven report series.

14-Day Free Trial

No credit card required. Complete access to articles, breaking news and industry data.