The three promoters are JPA Holdings Pvt Ltd, Nikhil Mansukhani and Anita Mansukhani.
The regulator conducted a probe in the shareholding of Man Industries during June to September 2010.
It observed that the shareholding of the company's promoters increased from 51.29 per cent to 55.18 per cent due to acquisition of shares in open market as well as by conversion of warrants.
Under Substantial Acquisition of Shares and Takeovers (SAST) regulations, it is mandatory to make an open offer if the promoters' shareholding crosses the threshold limit of 55 per cent.
However, the promoters failed to do so.
The promoters argued that they belonged to two different groups and hence should not be considered as persons acting in concert (PAC).
Rejecting the argument, Sebi said,"both groups were acting in concert and their shareholding has to be taken as a whole and thus the noticees have breached the threshold of 55 per cent thereby violating … SAST regulations.
"By not giving an open offer … the noticees have evaded buying of 20 per cent of shareholding (1,09,56,975 shares) from public at the price determined as per SAST regulations," Sebi noted in an order dated December 21.
Accordingly, the Securities and Exchange Board of India (Sebi), imposed a penalty of Rs 10 crore on the promoters to be paid "jointly and severally".