TXU, the Texas-based energy group, on Monday launched a campaign to persuade investors to back its $45bn buy-out by private equity groups KKR and TPG Capital, ahead of a vote on the deal scheduled for early September.

In spite of concerns that turmoil in the credit markets might force a renegotiation of the deal at a lower price, some TXU investors, including Franklin Resources, a large shareholder, have been pushing for a higher price.