Here are lists of the five most-improved and five most-deteriorated bond fund ratings from May 31 to June 30.

The most-improved bond fund this month is the Wells Fargo Advantage CA Tax Free Money Market Trust. This fund moved up six notches to A+, "Buy", from C+, "Hold", in the prior month's ratings. This fund seeks to generate income exempt from federal and California income taxes.

The remaining funds on the upgrade list each climbed five notches. Of those only one traveled all the way from a "Sell" rating of D+ up to a "Buy" rating of B. That fund is the FPA New Income ( FPNIX). With $2.04 billion in net assets, the fund is allocated to 38.95% mortgage-backed, 28.59% agency, 3.23% derivatives, 2.90% U.S. Treasuries, and 1.41% corporate debt. The remainder is in cash and equivalents. Their duration target is between 2 to 5 years for their debt portfolio.

The most-deteriorated list includes funds being downgraded to Sell from Hold. The largest fall in June bond ratings was experienced by the RidgeWorth Limited-Term Federal Mortgage Securities Fund ( SLMTX) dropping eight notches and bottoming out at a rating of E- from C+ for May. More than 90% of the portfolio is invested in mortgage securities.

Also, prominent on the downgrade list are several classes of PIMCO International StockPLUS Total Return Strategy Funds ( PISIX). These are portfolios of equity-based derivative instruments backed by investments in, mostly U.S., fixed income securities.

Top 5 Open-End Bond Mutual Fund Upgrades
Fund (Ticker) Current Rating Previous Rating Objective
Wells Fargo Avtg CA TF MM Tr (No Ticker) A+ C+ Tax Free Money Market
FPA New Income Inc (FPNIX) B D+ General Bd - Investment Grade
JPMorgan 529 Inf Pro-Fee Struct A (No Ticker) C E+ US Government - Long
American Century Tgt Mat.-2025 Inv (BTTRX) C- E US Treasury
Principal Sh-Trm Bd Fd A (PLTBX) D+ E- General Bd - Investment Grade
Source: TheStreet.com Ratings

Top 5 Open-End Bond Mutual Fund Downgrades
Fund (Ticker) Current Rating Previous Rating Objective
RidgeWorth Ltd-Trm Fed Mtg I (SLMTX) E- C+ General Mortgage
PIMCO Intl StkPlus Tr Strat Inst (PISIX) E- C General Mortgage
PIMCO Intl StkPlus Tr Strat D (PIPDX) E- C General Mortgage
Van Kampen Senior Loan Fund A (VSLAX) E- C Loan Participation
PIMCO Intl StkPlus Tr Strat C (PIPCX) E- C General Mortgage
Source: TheStreet.com Ratings

For an explanation of our ratings, click here.
Kevin Baker became the senior financial analyst for TSC Ratings upon the August 2006 acquisition of Weiss Ratings by TheStreet.com, covering mutual funds. He joined the Weiss Group in 1997 as a banking and brokerage analyst. In 1999, he created the Weiss Group's first ratings to gauge the level of risk in U.S. equities. Baker received a B.S. degree in management from Rensselaer Polytechnic Institute and an M.B.A. with a finance specialization from Nova Southeastern University.

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