At all time highs all holders are profitable. There is little fear to drive them to sell.
There is no selling pressure on the holders of current positions so they tend not to sell.
With the majority sitting on their current positions short sellers tend to be the primary ones selling.
Short sellers are forced to buy back at higher prices later creating buying pressure.
With the market holding key support levels stop losses are not hit so little selling pressure is coming from properly placed stop losses or trailing stops. They are letting winners run.
The pressure is on traders and investors that missed the move to chase and buy at higher levels when they under perform the market day after day as it goes higher.
Buyers are waiting to buy dips with pull backs at many levels so they can get in at the first opportunity. This creates support at levels on buyers wish lists that want back in.
All the central banks are on the side of the bulls. You can’t fight the FED.
Bull markets have no long term resistance levels.
When stocks are under accumulation it is a long process for them to start being distributed again. It is a path mixed with many strong rallies. The short side of bull markets is not where the money is. The short side of bear market is not even an easy path.