Carl Icahn may be licking his wounds after disappointing earnings from eBay and Netflix caused investors to bail on those stocks. But another one of his most famous investments has been getting outright walloped over the past few weeks. And it might get worse as oil prices continue to fall.

Transocean is the second-worst performing stock in the S&P 500 this year. Shares in the offshore drilling company are down 10 percent in the past week as oil prices plummet. So far in 2014, the stock has lost an alarming 43 percent. And for Icahn, who owns over 21 million shares, his big bet on Transocean has cost him more than $400 million since January.

David Seaburg, head of equity sales trading at Cowen and Company, thinks the worst isn't over for Icahn and other Transocean investors.

"This stock is going lower," Seaburg said. "There's no question about it."

With oil prices down 19 percent in the last three months, capital expenditures in exploration and production are called into question, Seaburg said, adding that has led to a glut in offshore rigs. "There is a massive amount of rigs on the market," he said. "They've got the second-oldest fleet. So they're in some trouble."

Seaburg also sees trouble ahead for the company's higher dividend, which currently yields more than 10 percent thanks to Icahn's pressure. In November 2013, Icahn successfully pushed the company to raise its dividend by 33 percent to $3 per share.

"There have been some concerns about a dividend cut," Seaburg said. "This stock is going to go lower until there's some clarity there from that perspective."

The technicals are equality bleak, according to Richard Ross, global technical strategist at Auerbach Grayson.

"There's nothing right now in the short- or the long-term technicals to suggest that a reversal in this pervasively bearish trend is imminent in any way, shape or form," said Ross, a "Talking Numbers" contributor. "I would avoid this stock. In fact, I would probably take it off your screen. … This one looks like it's going to do nothing but continue to go down."

Ross notes that the stock has been trading below is 20-day moving average for the last four months, a bad sign that there is heavy momentum to the downside.

But what makes Ross really dislike the stock is what he sees in its 20-year chart. He believes $26.50 per share is its critical support and will likely break below it.

"The technicals suggest there's further downside here both in the short and long term," Ross said. "I would avoid it."

Transocean declined to comment to CNBC.

To see the full discussion on Transocean, with Seaburg on the fundamentals and Ross on the technicals, watch the above video.

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