We all wish only longs were buying and selling BOTY. When you been trading stocks for decades you realize most stocks with decent volume are shorted at some point. That included OTC pink sheets stocks.
For the most part Market Makers are primarily shorting small OTC stocks in increased frequency. Many OTC companies try to market themselves by way of Investor marketing campaigns and newsletter features to generate awareness to their business and brands. They can easily run up stocks price by shorting then cover when necessary sometimes time end of day or week when s/p decline.
Those daily short # on OTC report may not be 100% accurate each day due to broker report delays and time zones reporting.
However the report are usually correct in percent of total daily volume and updated next day.