Top CITU leader A. Anandan, however, defended the CITU workers and said their people will never do such a thing.
The MD of Muthoot Finance, George Alexander's vehicle was nearing his office, when a stone landed on it breaking the windscreen and causing injuries to the back side of his head.
Alexander was seated in the front seat.
An employee of the company whose vehicle was following Alexander's vehicle said three vehicles were attacked.
"The stone was a very big one weighing around five kilograms and was meant to finish him. We identified the person to the police, but since CITU is the ruling party's trade union, the police never acts. In the past one week 20 of our staff who are not part of the strike have been attacked," said a company official.
For the last few months, a section of the employees with support from the CITU the trade union of the CPI-M has been protesting against the indiscriminate transfer and dismissal of a few employees by the management.
"We have no role in this stone attack and we do not know who is behind this," said a protesting employee.
The protesters are staging a protest about 50 metres from the head office of Muthoot Finance, after the Kerala High Court directed the protesters to keep away from the office.
Alexander is currently admitted to a hospital and is being treated.
The incident took place just days ahead of a key investment meet, here over two days, on Thursday.
Leading industrialists Kochu Ouseph Chittilapally said: "This is nothing new to Kerala and I myself had faced numerous such issues.
"This is exactly why, investors are wary of coming into Kerala and incidents like these don't augur well for either the state or for the investor."
Muthoot Finance has 3,600 branches in the country, of which 600 branches are in Kerala. It employs over 30,000 people across the country.
The Muthoot management has stated that the unrest has been going on for the past three years owing to which the company has lost 66 per cent of its business in Kerala, that contributed 11 per cent of their all-India business when the strikes began in 2016, which is now down to four per cent.
However, Muthoot Finance as a company has grown by 50 per cent during this period (between 2016 to 2019) from Rs 25,000 crore to Rs 35,000 crore.
( With inputs from IANS )