Ann: Update - Notification of buy-back - BRK, page-13

yep, not meeting the market like they said they would.
Now it's likely some opportunistic traders brought cheap shares that they will try and dump one or two pips higher for a decent profit. Makes any sp appreciation harder for us and means BRK will likely have to buy those shares at a higher price later when they could have gotten them at 1.1.
That is assuming they either intend to expand on the buyback or perhaps they now believe the sp will stay around this price indefinitely, which will be the case until they make a major monetisation announcement, a fact they are likely aware of.
If they know they don't have a big announcement coming they may well be dragging this buyback out and allowing the sp to be pushed down on purpose in order to maximise the buyback by intentionally letting the market capitulate.