(MONEY Magazine) – Pioneer High Yield

ASSET INCREASE SINCE JANUARY 2003: 132% This $8.7 billion fund is now one of the largest portfolios investing in the "junk" niche of the bond market. Manager Margie Patel says the extra money isn't a problem. But competitor T. Rowe Price High Yield closed its doors at $4 billion back in late February.

ALTERNATIVE: The $1.7 billion Northeast Investors, managed by Ernest and Bruce Monrad, ranks in the top 25% of its category over the past 10 years.

Royce Low-Priced Stock

ASSET INCREASE SINCE JANUARY 2003: 94% Manager Whitney George has put up impressive numbers over the years by buying a combination of small- and microcap names. But now the fund has $3.5 billion in assets. George concedes that this fund will have to change its approach to microcaps.

ALTERNATIVE: At the more nimble $32 million Royce Value Plus, George and co-manager James Skinner have 49% of assets in microcaps.

Fidelity Leveraged Company Stock

ASSET INCREASE SINCE JANUARY 2003: 2,064% This $1.7 billion fund specializes in stocks of companies with a bunch of debt; it makes big bets in the media, telecom and utilities sectors. That concentrated strategy could be tougher to execute with more assets.

ALTERNATIVE: This unusual fund would be hard to replace, so we can't recommend selling it just because of its size. But investors should keep an eye on how it performs. --A.C.