Distribution growth is what drives master limited partnerships’ (MLP) returns higher over months and years. The key is the health of the underlying business, i.e. whether it’s capable of sustained growth and balance-sheet strength.

That’s why we spend so much time talking about fundamentals, particularly around earnings-reporting season.

There are, however, a number of technical factors worthy of note. This month we present a table highlighting numbers for MLP Profits Portfolio Holdings, “Portfolio Technicals.”

Here’s what’s covered:

Market capitalization (in billions of US dollars)–This is basically the market value of the MLP, measured by multiplying the total number of units by the unit price.

Larger MLPs are usually more adept at weathering market cycles. Smaller MLPs have an easier time moving the profit meter with new projects, and a low market cap can attract takeover interest as well.

Shorts/Float–This measures the total short volume as a percentage of total shares of stock in circulation. Short sellers borrow units of an MLP and sell them in the market, with the goal of buying them back later at a lower price.

Higher short volume indicates more bets against an MLP, but if shorts are wrong they can be forced to sell at rising prices. A very high volume of shorts can cause a short squeeze, as short sellers are forced to buy at any price to stanch losses.

Institutional Ownership–This measures mutual funds and other large shareholders’ percentage ownership of each MLP. Higher numbers can indicate greater volatility.

Insider Ownership–I like to see large percentages of insider ownership, but the larger an MLP is the more spread out its ownership is likely to be and the less the influence of insiders.

Note that the percentage shown for Enterprise Products Partners LP (NYSE: EPD) doesn’t include EPCO Holdings, the primary vehicle of the Duncan family for owning the stock. EPCO held 30.98 percent of Enterprise Products at last count.

Insider Additions–This shows the percentage change in insiders’ total holdings of a company over the past six months. Obviously, I like to see a rising percentage here, though a falling percentage isn’t necessarily the kiss of death.

Analyst Buy–Hold–Sell–Starting from the left, the first figure shows the number of analysts that rate the stock a “buy,” the second shows the number of “holds” and the third the number rating the stock a “sell.”

I like to see more “buys” than “holds” or “sells,” all else equal. However, a large number of skeptics can bring a lot of upside by shifting sides, should a company beat expectations. That’s been a big factor behind Buckeye Partners LP’s (NYSE: BPL) resurgence in recent months.

Beta–This is a measure of volatility relative to the S&P 500. Higher numbers indicate greater volatility. Not surprisingly, Conservative Holdings tend to have lower betas than Aggressive Holdings, due to less commodity-price sensitivity.

2012 Total Return and 2013 Total Return–This is the bottom line for each recommendation and provides a good gauge for price momentum of these Holdings.

Note that our return for the first quarter of 2013 is nearly three times the full return for last year. That should sound a cautionary note for those eager to plow major funds into MLPs now, and it should ring especially loudly for those MLPs that have added big gains this year to sizeable total returns last year.

So what do these numbers tell us now?

On the bullish side, we’ve seen net insider buying for most recommendations over the past six months. Analysts also remain pretty positive for most of our MLPs, even those with huge recent gains, such as Genesis Energy LP (NYSE: GEL). But there’s been a noticeable cooling toward some, such as Spectra Energy Partners LP (NYSE: SEP) with one “buy” versus 11 “holds” and two “sells.”

Institutions are loaded up on some MLPs but still relatively underweighted in others. As big money controls most of the daily trading in the market, their buying has no doubt been among the biggest factors driving current MLP prices higher recently.

The flipside of that, however, is that they tend to be fickle owners. They have to produce returns to meet benchmarks, so they’re not likely to ride something back down after a bull run.

MLPs’ business plans, in other words, may be built to last with distribution growth locked in. But their unit prices can be anything but steady, as big institutions rush in and then rush out.

Big beta MLPs may be most vulnerable to a rush out. But I’d look very carefully at any MLP that’s really run up in recent months. They’re almost certainly the biggest beneficiaries from buying momentum now, which could quickly turn into selling on any disappointment.