There's a lot going on in the mutual fund world, and if you miss something, it could end up costing you money. To keep you up-to-date and on top of things, below we scope out some of the recent happenings in the mutual fund industry during the past week and how they may affect your portfolio.

Another loss for AXA Rosenberg
The ax has fallen yet again on AXA Rosenberg. Vanguard recently announced that it was firing AXA as subadvisor on three of its actively managed funds, Vanguard Explorer (VEXPX), Vanguard U.S. Value (VUVLX), and Vanguard Market Neutral (VMNFX). AXA Rosenberg has been under fire for its delayed response to a coding error in one of its quantitative models used to manage money. Apparently, the firm failed to notify clients of the error, which occurred back in 2007. Vanguard is just the latest in a long string of clients that have released AXA Rosenberg from its duties as a result.

So what does this mean if you own any of these three funds? Well, if you own small-growth fund Vanguard Explorer, the change probably won't affect you too much. The fund currently utilizes six other subadvisors, which will divide AXA's 12% share of assets, so shareholders shouldn't see any substantial changes in the portfolio. For example, Explorer currently invests heavily in the tech sector, choosing ON Semiconductor (Nasdaq: ONNN) and scientific instrument manufacturer Bruker (Nasdaq: BRKR), both of which trade at P/Es lower than their respective industry average and boast growth rates meaningfully higher than their peers. This positioning shouldn't change much as a result of this shift in management.

Conversely, AXA Rosenberg was responsible for more than half of fund assets at Vanguard U.S. Value and Vanguard Market Neutral. That money will now be going to Vanguard's Quantitative Equity Group, which managed the remainder of assets in those two funds. While Vanguard's quant group has a fine long-term track record, investors may see some changes around the edges of their funds as the managers reposition the portfolio. At any rate, Vanguard has better large-cap funds than U.S. Value, and with its $250,000 minimum, Vanguard Market Neutral is out of reach of most retail investors. Fundholders here shouldn't necessarily panic over the management change, but they may want to reevaluate their reasons for holding these funds and seek out other options.

Investors still following the herd
Investors are still running scared and stuffing their money into bonds, according to the latest Morningstar fund flow data for July. The numbers indicate that U.S. equity funds saw roughly $12.4 billion leave their doors in July alone, while $22.3 billion in assets made its way into taxable bond funds. Muni bond funds accounted for another $3.9 billion in inflows, while $4.9 billion poured into money market funds. There may be a lot of uncertainty in the market right now, but one thing is very clear: Bonds are where the action is, and investors show no sign of easing up on the torrent of money flowing into this sector.

While this flight to safety is understandable, given the current slowdown in the economic recovery and pervasive fear and uncertainty, many investors may be setting themselves up for disappointment down the road. Even Bill Gross, manager of the hugely popular and plain old huge fund PIMCO Total Return (PTTAX), has admitted that the bond market's best days are likely behind it. While every investor should have some fixed income exposure, bonds aren't going to be able to generate the returns investors need for long-term portfolio growth.

Even if you're leery about investing in the stock market, make sure some of your new money is going into well-diversified stock funds. The inexpensive Vanguard Total Stock Market ETF (NYSE: VTI) or the SPDR S&P 500 Index (NYSE: SPY) are two terrific ETF options for long-term equity investors. Bonds should be an important part of your portfolio, but not as important as most investors are apparently making them out to be.

New funds from an old name
In other fund news, the venerable American Funds fund family has filed with the SEC to launch two new fixed-income funds: one fund that invests primarily in mortgage-related securities, and another that will invest in New York State municipal bond issues. American Funds rarely adds new funds to its existing lineup, so it's notable that the shop is adding two offerings. This move may be part of an effort to stem fund outflows; investors have pulled roughly $34 billion in assets from American Funds in the past year. Given that bonds are the place to be right now, American Funds may also be responding to perceived investor demand.

While American Funds has a number of highly rated and very successful funds in its line-up, most of those funds tend to be equity funds. The shop's bond offerings aren't quite as compelling. There are a handful of solid and reasonable choices such as American Funds Capital World Bond (CWBFX), American Funds American High Income Trust (AHITX), and American Funds Intermediate Bond Fund of America (AIBAX). But none of these funds are standout performers.

So I'd recommend waiting on the shop's two new offerings for now. American Funds' well-established investment approach should ensure that the new funds won't tank, but I would wait to see how the funds shake out a bit before investing. In the meantime, bond investors can still get wide market coverage via ETFs. iShares Barclays Aggregate Bond Index (NYSE: AGG) is a good all-purpose bond fund, while investors looking for a mortgage fund might want to consider the Vanguard Mortgage-Backed Securities Index ETF (NYSE: VMBS) or an actively managed fund like TCW Total Return Bond (TGLMX).

For more insider investing and personal financial planning tips, check out the Fool's Rule Your Retirement service, which provides top-notch retirement and mutual fund advice. You can start your free 30-day trial today.

Amanda Kish is the Fool's resident fund advisor for the Rule Your Retirement investment newsletter. Amanda owns shares of iShares Barclays Aggregate Bond Index ETF. The Fool has a disclosure policy.