How does the old saying go — birds of a feather flock together? If it’s true, then that’s good news for the likes of Exelon (NYSE:EXC), Constellation Energy (NYSE:CEG), Dynegy (NYSE:DYN), and a handful of the more obscure wholesale electricity producers/energy traders.

Were any of these stocks perking up on their own, it could be dismissed as volatility. To see the group as a whole finally start to take a bullish shape, though? That’s a sign of something bigger brewing — perhaps something with some trade-worthy longevity.

Like most groups, energy trader stocks suffered in 2008. And like most groups, the independent power producers’ stocks started to recover in early 2009. Unlike most industry groups though, these stocks faltered in 2010; the S&P 500 Power Producers and Energy Traders Index actually lost 19% last year vs. the market’s gain of 11%.

The initial assumption might be that there’s a fundamental flaw here. To a bargain hunter that understands ‘value’ and ‘share price’ aren’t always the same things, though, that 2010 lull actually opened a window of opportunity. The pot is sweetened by the fact that the index has managed to make well-paced progress this year in spite of the market’s woes. In fact, the index itself is knocking on the door of a new multiyear high of 71.50. Considering the size and scope – and now momentum – of this bowl-shaped move, however, the odds are good we’ll see the index punch through that ceiling.

Unfortunately, there’s no direct investment in this index. The good news is, there are plenty of stocks that are setting up the same trade we’re seeing with the group’s chart.

First however, a few words on Constellation Energy — it’s been on fire of late because it’s the target of a renewed takeover bid from Exelon. Since the April announcement, the potential deal has morphed into what’s now being called a union, but it doesn’t change the fact that Constellation’s shareholders are loving the higher and higher bid price they’re able to command, which is now well beyond the initial buyout price presumed to be around $37 a share.

While there may not be enough upside left for newcomers to Constellation, where we see one merger or acquisition, we’re generally apt to see more. Even if we don’t see more M&A, though [holding a stock strictly because you think it’s a buyout candidate is a lousy reason to own anything], a handful of these charts are starting to reflect their underlying companies’ success.

One of them is Trans Alta (NYSE:TAC). The stock’s been flat for the year so far, though going back to last year we can see a modestly bullish channel [framed in yellow on our chart]. But if the $22.50 level can be knocked out, this chart is actually something of a coiled spring.

The trigger for that move should be another big quarter on the earnings front. Trans Alta’s most recent quarter topped off the strongest four-quarter stretch we’ve seen since 2008. It hints that the earnings tide has been turned, even if TAC is priced at a tad frothy projected price-to-earnings ratio of 27.9. (It also topped estimates on its past two quarters, so the forward-looking P/E may not be doing the company justice.)

GenOn Energy (NYSE:GEN) is another of those ‘turning the corner’ names, in terms of its chart as well as earnings. Oh, it’s still losing money, but the stock itself has managed to push back above all of its key long-term moving averages and lay the foundation for a bigger move higher simply because the market is encouraged by the shrinking losses here. At its current pace, it may swing to a profit again next year.

Dynegy has finally shrugged of its stagnation between $5.40 and $6.20, rallying to $6.38 this week, which is within striking stance of new annual highs. And, given the length of the consolidation phase and the strength of the recent breakout move, there’s a ton of upside potential packed in here despite the fact that the losses are getting bigger. Once again, traders are focused more on the likely success of the future and less on the recent failures/losses — a real testament to the power of industry ‘groupthink’.

And yes, even though Exelon is going to have to lay out some cash if it wants Constellation (though the first two attempts failed, so you never know), we’re getting major clues here that this stock is also pulling out of a long-term funk. We’ve seen higher lows since mid-2010, and a long-standing resistance line (red) was snapped earlier this year — all of which happened despite the company sinking further into the red during that time. The group’s influence has commandeered this stock, too.

This sector may be off the radar for most investors, but a rising stock is a rising stock. Sometimes it’s the obscure stiff that pays off best, but investors have to be willing to accept the clues they’re given — like long overdue rebounds.