After witnessing around a 10% surge, Kalanithi Maran-owned Sun TV stock prices dropped by 8.08% to Rs 393.
Stock price shot up after exit polls predicted victory for Maran's uncle M Karunanidhi and the DMK during the Assembly election. On Thursday morning, stock prices started falling after counting started.
Initial counting showed AIADMK was leading in 73 seats, while DMK was leading in 63 seats.
Sun TV, which has a dominant presence in southern markets, is promoted by DMK chief M Karunanidhi's grand-nephew Kalanithi Maran.
Tuesday's gains topped a phenomenal rise for the stock over the past two weeks as election fever peaked in Tamil Nadu ahead of Monday's polls. Four out of five exit polls, released on Monday, predicted that the DMK-led alliance was likely to win a majority in the new Assembly.
On Tuesday, the shares gained 10% to close at Rs 431.6. On the NSE, the gains were slightly higher at 10.4% at the close of Rs 435 apiece.