A recent uptick in activity in assorted Vanguard ETFs via some creations in the marketplace presents an opportunity to delve into one of these funds, which has had a particularly successful 2013 in terms of raising new assets. VXF (Vanguard Extended Market, Expense Ratio 0.14%) is categorized in the “Mid-Cap Blend” space, with exposure specific to U.S. listed equities.

The fund has been around for some time, debuting in 2001 although it has reeled in an impressive $1.83 billion year to date via creation activity, making its total asset base approximately $2.99 billion. The concept of “Extended Market” probably resonates with advisors whom aren’t even ETF users, as VEXMX (Vanguard Extended Market Index Fund, Expense Ratio 0.28%) is a popular mutual fund offering of the company, and has been for more than a decade.

In any case, VXF has sprung to life this year in terms of attracting new assets and growing substantially in size, but then again, the U.S. Mid-Cap Equity space in general has been pulling in new assets hand over first this year when you really look at it.

The top fund in the Mid-Cap category, IJH (iShares Core S&P Mid Cap, Expense Ratio 0.15%) has seen more than $4.4 billion enter the fund year to date, giving it a giant asset base of $21.8 billion. It also does not hurt IJH in that it is a model component of a prominent managed ETF tactical strategy run by a well-known ETF strategist, and the fund often trades enormous size on monthly re-balances several times a year now consistently.

The next largest fund in the space, MDY (SPDR S&P MidCap 400, Expense Ratio 0.25%), even despite the recent outflows, has still seen a net of $1.25 billion enter the fund. Likewise, the number three fund in the space in terms of asset size, IWR (iShares Russell Midcap, Expense Ratio 0.23%) has attracted about $580 million in net new assets in 2013.