WASHINGTON, (Reuters) – British energy giant BP  Plc’s stock price plunged to a 14-year low in U.S. trading yesterday amid concerns over its ability to  meet mounting  costs of the giant Gulf of Mexico oil spill.

President Barack Obama’s administration, getting tough as  polls show public disapproval over its handling of the worst  oil spill in U.S. history, threatened to impose new penalties  on the company.

BP depositary shares trading in New York fell nearly 16  percent to close at $29.20, their lowest level since August  1996, on growing worries about the costs the company will have  to assume. BP said last week it has “plenty of” cash to deal  with the problem and the Obama administration has made similar  comments.

A BP spokesman said “nothing has changed” since Friday and  restructuring experts agreed that by running the numbers alone,  BP looked able to handle the financial damage. But such  confidence was not evident in the market.