Nearly â‚¬100m has been wiped off the market capitalization of the Oxfordshire-based team since it floated 24pc of its shares in March at a price of â‚¬24.38. It closed on Friday at â‚¬15 per share following a 10.7pc drop over the past month.
The biggest casualty of the falling share price has been Dutch investment firm Cyrte which was founded by the billionaire John de Mol.
Cyrte became the biggest single investor in the Williams flotation by buying 5pc of its shares.
The falling Williams share price has severely dented Cyrte's fortunes and its stake has lost â‚¬4.7m of its value since it was acquired.
Williams – the second most successful F1 team – goes in to next week's Italian Grand Prix in ninth place with less than half the season left. It last won a race in 2004 and Scott Garrett, former head of marketing for Williams and vice president of brands at Heinz, says he does "not believe they will ever have the budget [to win again]".
In contrast to most of its rivals, which get larger payments from sponsors and their owners, prize money is believed to be Williams' biggest single source of revenue.
"The sorry state of the WF1 equity price indicates a team that is more desperate than confident, and confidence is critical when presenting oneself to sponsors and asking them for money," said Mr. Garrett. The Telegraph