The eight-week rally spilled over into other equity markets, but rising stock prices aren't the only marker of investors' sharpening appetite for risk.

Credit spreads have also tightened, indicating a greater willingness on the part of commercial banks to lend. Tuesday, three-month dollar LIBOR (London Interbank Offered Rate) slipped below 1%, shedding 44 basis points (0.44%) since the beginning of the year. At the height of the credit crisis in October, three-month dollar loans were priced as high as 4.82%.

Traders have moved from the relative safe haven of the greenback to higher-yielding resource-linked currencies like the Aussie and Kiwi dollars and the South African rand. Yields on U.S. Treasury securities, as a consequence, have jumped to levels not seen since November.

The Fed Funds traded rate - the actual price at which excess reserves are loaned between banks - has risen toward the top of the Federal Reserve's 25-basis point target range, after being offered at bottom-scraping rates for weeks.

Commodities - that is, certain commodities, such as crude oil, base metals and the softs - have awakened to turn upward. At the same time, interest in safe-haven gold has been eroding.

The renewed interest in commodities has been reflected in the price trends of broad-based exchange-traded products (ETPs).

Among the half-dozen notes and funds with trading histories of at least 200 days, five have broken to the upside of their 50-day moving averages. None has yet risen above its 200-day mark, the threshold for heralding a primary bull market. The one exchange-traded note (ETN) now trading below its 50-day average is paradoxically the one closest to starting a bullish trend.

So, which commodity exchange-traded fund (ETF) or note is the most sensitive bellwether of a nascent commodity bull market? Read on ...

ELEMENTS S&P CTI ETN (NYSE Arca: LSC)

The ELEMENTS note is an obligation of HSBC USA and is designed to replicate the returns generated by the S&P Commodity Trends Indicator Total Return Index. As featured in "A Real Commodity Moneymaker," this long-short product simulates real-world commodity trading. The index tracked by this note comprises 16 commodity futures grouped into six sectors. With the exception of the energy sector, each segment is positioned either long or short monthly, based on its price behavior relative to its moving average. The index methodology countenances only long or flat positions for energy; shorts are not permitted.

Presently, and for some time, LSC's underlying index has been flat energy and, as a consequence, the ETN has outperformed the long-only products when petroleum product prices swooned.

iShares S&P/GSCI Commodity-Indexed Trust (NYSE Arca: GSG)

The iShares ETF tracks the performance of the S&P/GSCI Excess Return Index, by holding futures skewed heavily (66%) toward energy contracts. The fund's underlying index comprises two dozen different commodities and is production-weighted to reflect each commodity's relative importance in the world economy. Agriculture, excluding soft commodities and livestock, at 18%, is the index's second-weightiest sector.

iPath S&P/GSCI TRI ETN (NYSE Arca: GSP)

The iPath note, the unsecured debt of Barclays Bank plc, is based upon the total return version of the S&P/ GSCI, which includes incremental return earned from holding futures collateral in U.S. Treasury bills.

GS Connect S&P/GSCI Enhanced Commodity TR ETN (NYSE Arca: GSC)

Another variant of the S&P/ GSCI acts as the basis for an ETN issued by Goldman Sachs. The Enhanced Commodity Total Return Strategy Index reflects the returns earned by holding the same futures contracts that are included in the S&P/GSCI. This index variant, however, uses a roll mechanism in an attempt to boost returns and sidestep the corrosive effect of contango.

The index methodology employs a rules matrix that dictates specific roll strategies for each commodity in an attempt to take advantage of historical and structural pricing differences among the various contracts.

PowerShares DB Commodity Index Tracking Fund (NYSE Arca: DBC)

iPath Dow Jones-AIG Commodity Index TR ETN (NYSE Arca: DJP)

This Barclays-issued note is linked to the Dow Jones-AIG Commodity Total Return Index, a benchmark comprising 19 futures allocated to six sectors. Though the index is largely production-weighted, no one sector can represent more than 33% of the benchmark's total weight. Limited exposure to energy in 2008 thus provided some degree of cushioning compared to products based upon other indexes.

Broad-Based Commodity ETPs

Broad-Based Commodity ETP Performance As Of May 4, 2009

Since its inception last year, the ELEMENTS S&P/CTI ETN has been the least risky commodity investment, aided in no small part by its recent avoidance of energy exposure. Though the note is presently underwater, it was, in fact, 20% above its launch value in last year's fourth quarter.

Oddly enough, the riskiest ETP, measured by its volatility cost, is the iPath Dow Jones-AIG Commodity Index TR ETN, a note whose current price is second-closest to its 200-day moving average.

So, what product reflected investors' increased appetite for risk?

A single ETP - the GS Connect S&P/GSCI Enhanced Commodity TR ETN - is in positive territory both for the year and when measured against its 50-day moving average. The Goldman Sachs note is the least active ETP in the group, swapping little more than 26,000 notes on an average day. Still, as indicated by the ETN's liquidity index, a trade of over 14,000 notes would be required to move the bid/ask spread 1%. There's plenty of room for fairly large trades to be accommodated by the ETN's market makers.

Although it's premature to call for a full-fledged resumption of the commodity bull market, these ETPs are, on average, only about 20% below their 200-day moving averages.

If nothing else, broad-based commodity ETPs are closing in fast on the bull's tail.