Investors continued to dump the stock amid rapidly fading confidence in the firm's ability to manage Japan's worst ever nuclear accident, with the stricken Fukushima Daiichi plant still emitting high levels of radiation.
Shares in TEPCO, which plunged another 17.66 percent on Wednesday, are now worth around a fifth of their pre-earthquake value.
The utility is expected to face a mammoth compensation bill amid reports it ignored earlier safety warnings over the Fukushima plant's exposure to tsunami risk and growing speculation that it will be nationalised.
The government on Tuesday said such a move was a possible "option".
TEPCO on Wednesday said it had secured 2 trillion yen ($24 billion) in bank loans but warned this would not be enough to keep the company running amid concerns the firm may collapse under the financial strain of the crisis.
Chairman Tsunehisa Katsumata told a press conference that "unknown" factors clouded the beleaguered firm's outlook, but stressed the company aimed to remain out of state hands.
"We are in a very severe situation," he said. "We want to remain private and will do our utmost to stay that way". Katsumata took the press conference on behalf of under-fire company president Masataka Shimizu, who was hospitalised on Tuesday with high blood pressure, dizziness and fatigue.
Shimizu, 66, has been heavily criticised for not having made a public appearance since March 13. Katsumata said it would not be long before Shimizu returned to his duties.
Shimizu fell sick earlier and took several days off from the joint task force that had been set up by the government and the company.
Local media had quoted a senior TEPCO official as saying Shimizu had been so ill that he had stayed "mostly in bed" in a separate room in the building where the task force was meeting.
Three weeks on from the March 11 earthquake and tsunami, the situation at Fukushima Daiichi remains unresolved after the plant's reactor cooling systems were knocked out, triggering explosions and fires and releasing radiation.
Katsumata said Wednesday that the stricken reactors 1-4 would be decommissioned given the damage and the amount of seawater poured on them.
He faced criticism that the company had supplied a flow of opaque and occasionally wrong information, including a misleading radiation reading, but denied TEPCO withheld details on the Fukushima situation.
"I am very sorry that there have been various mistakes and delays in the timing (of making announcements). But we have never concealed information," he told reporters.
Bowing several times to apologise, Katsumata denied there were any delays in management decisions to cool the reactors, following criticism of its handling of the Fukushima Daiichi plant.
"I personally do not feel that (our response) was slow. We operated the best we can," Katsumata said, though admitting some "unintended delays" due to the difficult conditions at the facility.