• by Wayne Friedman , Staff Writer, September 21, 2016

Donald Trump appears to be causing issues for TV stations.

As lots of industry observers note, the Republican presidential candidate just began spending some TV advertising dollars on this campaign -- this after virtually no spending over the better part of a year.

Now, some TV station groups are feeling the pinch. Sinclair Broadcast Group, the largest TV station groups in terms of number of stations, reported that advertising revenues would be underperforming in the third quarter -- in part due due to dips in political advertising.

On Tuesday, all this pushed Sinclair’s stock down a big 10%, to $25.99. And there were ripple effects for other local TV station groups: Tegna sank 3.8% to $20.54; Tribune Media was down 4.5% to $35.47; and Nexstar slipped 4.3% to $52.03.

But CBS’s Les Moonves say lower presidential ad activity isn’t having much effect on CBS’ local TV station projections, because there is more advertising coming from state and other local political campaigns.

Much of the bullishness for local TV station groups this year have come from the now every-other-year bump from Olympics advertising revenues.

In the digital age, TV stations groups increasingly have been looking for ways to hedge their legacy advertising and content businesses. Surely, political advertising in a nice complement. But websites, mobile apps, and future local OTT efforts have been the long-term promise from these outlets.

Is there enough here for TV stations to wean themselves from the ups-and-downs of periodic and seasonal advertising moves?