the effect of a stock buyback should never be to push the share price up. You're retiring shares at their current market rate, which should theoretically be neutral to the per-share price if we assume the market is pricing the stock appropriately.
I don't think that's right.
Assume we have a company with an earnings multiple of 20.
The company has 1,000,000 shares of stock and 1,000,000 in earnings.
The company is valued at 1,000,000 x 20 = 20,000,000.
Each share of stock is worth 20,000,000/1,000,000 = $20.00
Now the board if directors decides to buy 10% of the stock and retire it (this doesn't happen instantaneously but let's assume nothing else changes)
The company now has 900,000 shares of stock but the same 1,000,000 in earnings.
The company is valued at 1,000,000 x 20 = 20,000,000
Each share of stock is worth 20,000,000/900,000 = $22.22
The stock went up 10% because the value of the company did not change, but each share represents a higher % ownership in the company.
If instead the company declares a $1.00 per share dividend
The company has promised to give away $1,000,000 so they are now only worth 19,000,000.
Each share of stock is worth 19,000,000/1,000,000 = $19.00
So you still have $20 but it's $1 cash and $19 of stock.
The timing of the dividend is no secret. On a particular day the dividend will be distributed and the stock price will fall. As with the stock buyback, the company usually has discretion to repurchase up to a certain number of shares over a certain time period. It's much more nebulous and less instantaneous. There's even at least one ETF (PKW) designed to capitalize off of this:
The Index is designed to track the performance of companies that meet the requirements to be classified as BuyBack Achievers™. The Nasdaq US BuyBack Achievers
Index is comprised of US securities issued by corporations that have effected a net reduction in shares outstanding of 5% or more in the trailing 12 months.
If a company reduced its shares by at least 5% it was buying them because they thought the stock was underpriced, and hopefully after the 5%+ reduction they still take that view, and maybe the stock will continue to go up on that basis alone.
Over the last 10 years the S&P generated 11.9%/yr and as of September 30 had a P/E of 19.4
Over the last 10 years PKW generated 10.1%/yr and as of September 30 had a P/E of 13.5