Brokers are fighting tooth and nail for your business. But some of the battles in the Great ETF War of 2010 have crossed the line from being beneficial for investors to overkill.

On Thursday, Vanguard announced that it would add 20 new exchange-traded funds to its ETF lineup. With 16 new stock funds, three ETFs dedicated to municipal bonds, and a real estate-related fund, you might think that more choices meant more benefits for investors. But actually, many of the new offerings are redundant and completely unnecessary for regular investors.

Duplicating effort
In the past, Vanguard has done an excellent job of providing good coverage of the investing space. Typically, no matter what type of investment you want to own, you'll find one -- and often exactly one -- fund that will help you get the job done.

That's why these new offerings are such a disappointment. The objection I have to Vanguard's new ETFs is that for the vast majority of investors, they add absolutely nothing new that you need. Below, I've listed several of the new ETFs coming out, and which existing ETF you could buy right now that serves almost exactly the same purpose:


Covers These Stocks

Existing ETF That Already Covers Similar Stocks

Russell 3000 ETF

Total U.S. market

Vanguard Total Stock Market ETF (NYSE: VTI)

S&P 500 Value ETF

Large-cap value

Vanguard Value ETF (VTV)

S&P MidCap 400 Value

Mid-cap value

Vanguard Midcap Value ETF (VOE)

Russell 1000 Growth ETF

Large-cap growth

Vanguard Growth ETF (VUG)

Russell 2000 Value ETF

Small-cap value

Vanguard Small-Cap Value ETF (NYSE: VBR)

Source: Vanguard.

As you can see, whether you want large-cap stocks or small caps, growth or value, Vanguard accountholders can already find an ETF that meets their needs. So rather than truly expanding available choices for Vanguard investors, the vast majority of these new offerings will merely muddy the waters, leaving them with the challenge of trying to figure out whether they should follow indexes from McGraw-Hill's Standard & Poor's, Russell, or MSCI.

Catering to institutions
Vanguard clearly understands that most of those new offerings don't add anything particularly useful to its already extensive lineup. In a press release, Vanguard CEO Bill McNabb explained how the move was tailored toward investors with very particular objectives: "We recognize that institutional investors and financial advisors may have a preference for certain benchmarks, and our goal is to offer them best-in-class funds and ETFs based on a choice of leading index providers."

More importantly, the move has competitive ramifications within the ETF industry in two different ways. First, it pushes Vanguard's ETF family into more direct conflict with BlackRock's (NYSE: BLK) iShares and State Street's (NYSE: STT) SPDR line of ETFs.

In particular, Vanguard's S&P 500 fund launches a frontal assault on the landmark SPDR Trust (NYSE: SPY), which has had an average daily trading volume of more than $25 billion over the past three months. Similarly, the iShares Russell 2000 ETF (NYSE: IWM) is one of iShares' most popular funds, with around $5 billion in shares trading every day. Even if Vanguard takes just a small chunk away from those funds, it could add up to serious money.

Second, it responds to Charles Schwab's (NYSE: SCHW) price cuts on its own proprietary line of ETFs, which gave Schwab the status of lowest-cost ETF provider. Ever since its beginnings, Vanguard has long prided itself on being the cost leader in the mutual fund industry, and so letting Schwab undercut Vanguard's ETF offerings wasn't something it could allow to happen for very long.

What's the next step?
The interesting thing about Vanguard's move is trying to figure out who'll fire the next shot. At least for now, iShares and State Street still have a lead, having committed early to exchange-traded funds as a source of additional money management revenue. Vanguard, though, has had early success from its new commission-free ETF offer for brokerage account holders; and even though its mutual fund assets dwarf its ETF assets, Vanguard seems to believe ETF dominance is worth pursuing.

Through its partnership with Fidelity, iShares is defending its territory. That leaves the ball in State Street's court to decide whether it can meet the challenge or will simply fade into the sunset.

It's always smart to be careful. Make sure you know about this hidden danger in your portfolio.

Fool contributor Dan Caplinger is easily amused by financial silliness. He doesn't own shares of the companies mentioned. Charles Schwab is a Motley Fool Stock Advisor selection. The Fool owns shares of Vanguard Small Cap Value ETF. Try any of our Foolish newsletters today, free for 30 days. The Fool's disclosure policy is deadly serious when it comes to protecting you.