General Motors and Charter Communications are very different companies. According to the plans that both companies are pursuing in bankruptcy court, however, their shares will end up in the same place: worthless.

It’s hard, then, to explain the very different trading patterns. Charter shares fell to rock bottom before the March 27 bankruptcy filing and have stayed there, trading for between 2 cents and 5 cents a share. GM, on the other hand, has given investors a rollercoaster ride. It was at 75 cents on June 1, the day of the bankruptcy filing, but rose to $1.50 on Wednesday before sliding back to $1.15 today.

At that price, GM has a market cap of $714 million, which — as I noted in Tuesday’s column — seems completely irrational. Going back to our Charter comparison, the big automaker is currently worth 60 times as much as our local cable provider. In 2006, the ratio was just 14-to-1 and in 2000, it was just 5-to-1.

What’s more, I haven’t heard of any credible reason why GM should throw a crumb to the common shareholders. Taxpayers are financing the whole thing, bondholders are taking an extreme haircut and even the United Auto Workers is taking less than it is owed.

In Charter’s case, for a few pennies you can make a bet on the outcome of legal arguments that are already pretty far along. According to this Bloomberg bankruptcy roundup, a hearing is scheduled for June 17 on whether to appoint an equity committee, which would give shareholders a fair amount of leverage in court. Here’s Bloomberg’s description of the argument made by one shareholder:

Q Investments contends that Charter is solvent, as reflected by similar companies whose stock rose 67 percent from March 9 to May 18. The stockholder argues that Charter’s plan is a “sweetheart deal” that benefits bondholders and insiders while wiping out existing equity.