BP stock sank to its lowest point in 14 years Wednesday as investors feared the company would be overwhelmed by the costs of the oil spill in the Gulf of Mexico, perhaps forcing it to cut its robust dividend to pay for the disaster.

The stock dropped $5.45, or 16 percent — easily its worst day since the Deepwater Horizon rig exploded seven weeks ago. The company has lost half its market value, a stunning $95 billion, in that time.

On Wednesday alone, 238 million shares of BP changed hands, an extraordinary number that was more than double the company’s volume for some days earlier this month.

“It’s not time for logic. It’s not time for being rational,” Fadel Gheit, energy analyst with Oppenheimer & Co., said of the selling. “When people say run, you run too. It’s a mob mentality.”

Political pressure is building on BP to slash its dividend or suspend it altogether until the well is capped and hundreds of miles of coastline have been cleaned up. Some investors worry the billions of dollars in liabilities could wipe the company out.

The stock closed at $29.20, near its low for the day. Shares of Anadarko Petroleum, which owns a quarter of the sunken rig, fell 19 percent to their lowest level in five years. Transocean Ltd., which owns most of the rig, fell 8 percent.

“People are anticipating there’s a chance that BP, Transocean and Anadarko are going to bankruptcy,” said Scott Hanold, an analyst with RBC Capital Markets. “It’s feeding on itself now.”

He noted the cost to insure the debt of all three companies shot up Wednesday, a sign investors are increasingly worried the companies’ ability to pay off what they owe.

In Washington, the point man for the government’s response to the spill said BP was capturing more than 630,000 gallons a day from the gushing well, an elevated figure that could mean both BP and the government have vastly underestimated the totals so far.

Estimates for the total cost of the spill grow with every barrel that BP’s failed well belches into the Gulf and with each oil-covered pelican or turtle that washes up on a devastated beach.

Argus Research analyst Phil Weiss BP did exactly what it should not have with investors in response to the spill: “They over-promised and under-delivered.”

A BP spokesman at the company’s command center in Louisiana said he didn’t know why the share price plunged. BP told investors Friday that it has “considerable firepower” to cover the cost of the spill and to give funds to investors.