Cambria Global Tactical ETF (NYSE: GTAA) is an actively managed exchange-traded fund (ETF) launched under the AdvisorShares umbrella. It’s run by Mebane Faber and Eric Richardson of Cambria Investment Management who are best known as the coauthors of The Ivy Portfolio: How to Invest Like the Top Endowments and Avoid Bear Markets (Wiley, 2009). Faber and Richardson employ a global trend-following quantitative strategy that will encompass stocks, bonds, currencies, commodities and real estate from around the world. They’re not going to do any forecasting; the fund will basically jump into established trends.

Based on the fund’s prospectus, the managers have wide leeway to fully invest the fund or hold 100 percent in cash. Also, rather than rebalancing on a quarterly or monthly basis; the fund’s portfolio can be adjusted weekly.

The fund will feature a sliding management fee scale that will start off at 0.90 percent for the first $250 million in assets under management, before falling to 0.80 percent for the next $750 million, then to 0.70 percent for the next $4 billion and finally to 0.60 percent for all assets in excess of $5 billion. It’s by far one of the most equitable and responsible management fee arrangements I’ve seen from any corner of the fund industry.

Nonetheless, Cambria Global Tactical ETF will be rather pricey. The fund’s adviser has agreed to cap net expenses on the fund at 1.35 percent until Sept. 12, 2011. But because it’s a fund of funds, true gross expenses will likely run higher than that.

Despite its cost, the fund seems to be catching on with investors, with an average daily volume already topping 200,000 shares. Assets have risen to just over $17 million.

Cambria Global Tactical ETF looks like an expensive way to add alpha to your portfolio and its high cost reaffirms my doubts about actively managed ETFs.

Last Thursday saw the launch of Market Vectors Rare Earth/Strategic Metals ETF (NYSE: REMX). I won’t dwell on the new fund at length because I wrote about rare earth elements (REE) a few weeks ago, but I’m intrigued.

As I said then, “rare” is a relative term; rare earths actually occur in fairly high concentrations in parts of the world. Their rarity is based on low global production levels. China is the only country actively producing rare earths in significant quantities, and ramping up production in the US or other developed countries will be a long, multiyear process.

But there is a solid long-term thesis behind rare earth element (REE) investment and this ETF captures almost every publicly-traded company that’s involved in some aspect of the production or sale of REEs. With an expense ratio of just 0.57 percent, Market Vectors Rare Earth/Strategic Metals ETF looks like an excellent long-term holding, and its average daily volume is already building.

Finally, a new closed-end fund (CEF) that launched last week warrants your attention because it’s been wrongly identified as an ETF.  Sprott Physical Silver (NYSE: PSLV) allows investors to redeem shares for physical bullion and has received a warm reception since it began trading last Thursday.

While it is exchange traded and it is a fund, it is not an ETF in the classic sense. A typical ETF can create and redeem shares to keep supply and demand in balance, thereby keeping the shares from trading at extreme discounts or premiums to net asset value. But closed-end funds don’t have that mechanism. A set number of shares are issued at the initial public offering and that number can basically only shrink as shares are redeemed. As a result, huge premiums or discounts can build up, as you can see in the chart below that tracks the premium history of another fund, Sprott Physical Gold (NYSE: PHYS).

Additionally, the redemption process doesn’t favor individual investors. Redemptions are allowed only once a month on a 15 day lag, with prohibitively high fees on smaller transactions. Avoid Sprott Physical Silver.