As always : it depends .... on various parameters. Among others, the size of the buyback program compared to the float.
Normally, one would say, a buyback is good thing, since the company doesn't find any better investment for their cash than their own stock. Very confident about the companies future.
Others may say, if a company has no better idea to invest cash wisely than buying back own stock, the management seems not to be very innovative - bad for the company.
A buyback reduces the float of the stock and can ultimately result in more volatility ( less stock out there for those who are interested to buy, larger spreads and all other advantages / disadvantages of low float stocks )
A buyback program can also prevent a company from an unfriendly takeover. A buyback would be a strategic action in this case.
Often enough though, buybacks are announced when the shareprice has dropped significantly and investors are not anymore convinced about the companie's prospects.
They buyback shall restore trust in the companie's future among investors.
However, if the program covers only a small amount of the float, this won't help much unless the fundamentals of the company show signs of improvement along with the buyback.
It pays out to do some research on the reasons for a buyback before jumping on a rolling train.
regards &