Shares of India’s Zee Entertainment nosedived Tuesday after a proposed $10 billion merger with the local unit of Japanese giant Sony was called off.

The initial 30 percent plunge saw Zee lose as much as 55 billion rupees ($661 million) in market value. At least five brokerage firms, including Hong Kong’s CLSA, have slapped a “sell” rating on the stock.

The merger’s failure, reportedly because of disagreements over who would lead the new entity, has also reignited worries over Zee’s ability to thrive in an increasingly competitive entertainment market.

The collapsed deal leaves both Sony and Zee more vulnerable at a time when billionaire Mukesh Ambani-led Reliance Industries (RIL) is negotiating a merger with Disney’s India unit, Bloomberg News reported.

India’s entertainment market, worth tens of billions of dollars, is already one of the world’s biggest, while smartphone adoption is forecast to expand further in the coming years.

“Considering that Zee still has six billion rupees cash on books… we see no bankruptcy risks,” Ambit Capital research analyst Vivekanand Subbaraman wrote in a note.

“However, investors will find it very difficult to ascertain the fair value of Zee given uncertainties on the operator,” Subbaraman added, pointing to issues including the debate on whether CEO Punit Goenka will remain at the helm.