That is unlikely or otherwise illegal and someone will end up in jail for stock manipulation. Another explanation could be people or institutions are taking profits. It happens. That being the case, nothing prevents a company from buying low cost shares after they have announced the stock buy-back. It is a disincentive for shorts because the price typically increases when stocks are bought. So, how does some genius at SIRI get the PPS to decrease during an announced stock buy-back period?
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