TXU may be out of mind, but its not out of sight. The energy giant, bought by KKR, TPG and Goldman Sachs for $31.8 billion during the private equity boom, is now called Energy Future Holdings, and still reports earnings on a quarterly basis.

Second quarter results released last night, show a net loss of $3.3 billion, the vast majority of which was due to unrealized mark-to-market losses on forward natural gas positions. That’s similar to other firms in its sector — NRG which is the second largest generating company in Texas behind Energy Future — reported mark to market losses of $543 million in the second quarter. The recent rise in current natural gas prices affected many firms in the sector, such as NRG.

In most cases, its hard to work out how private equity portfolio companies are faring, unless they have publicly traded debt.

The other way of getting visibility into how these firms are doing is if they’re part of a publicly traded private equity firm, such as Blackstone.

Blackstone adjusts the value of its investments every quarter for accounting purposes, which hits it particularly hard when the market is down and highlights the companies not doing well. KKR will also be subject to public scrutiny later this year when it lists on the NYSE, and one of the companies with the most interest given its size and the volatile commodities market will likely be Energy Futures.