Belfast-based UTV says it is in talks which could lead to its TV business in Northern Ireland being sold.
If the deal goes through, STV would be the last Channel 3 broadcaster outside ITVplc's control.
Like STV, up until now UTV has guarded its independence and identity fiercely. Originally the Channel 3 network was a federation of regional franchisees.
Between 1993 and 2004, the regional stations based in England and Wales - including Border TV which serves southern Scotland - gradually consolidated into one company through a series of takeovers and mergers. At the end of the process, the company was named ITVplc.
Later ITVplc also acquired Channel Television in the Channel Islands leaving UTV and STV as the only independent companies in the network.
Parent company UTV Media - which also owns several radio stations - said this morning it was in talks which could lead to the sale of its television business. It had already been widely reported that ITVplc was the potential buyer.
Inevitably, there is bound to be renewed speculation over STV's future independence if UTV comes into ITV's ownership.
However industry watchers point out that STV has had to live with this sort of speculation for 20 years and still managed to retain its independence - sometimes against the odds.
The relationship between STV and ITVplc would not be directly affected by any takeover of  ITV by UTV.
Three years ago, STV entered into a new affiliation deal with ITVplc which led to a new, friendly relationship between the two companies. Previously it had become strained after STV started dropping popular network programmes.
Ironically, before the current management team took control of STV in 2007, a merger between STV and UTV was on the cards.
UTV Media has been hit by the cost of setting up a TV station serving the Irish Republic. It has led the company to issue several warnings that losses at the new station would be greater than originally anticipated.
Scottish broadcaster STV could soon be the only independent station left in the Channel 3 TV network.