More than 21,500 March 29 puts were sold in less than a minute yesterday, led by a single print of 19,000 that went for the bid price of $0.43. This is clearly a new position, as open interest in the strike was just 1,267 contracts before the trade appeared.
Now what can that mean? I say it is bullish! The seller of those puts is obligated to buy BX at 29 should it fall below the strike price. The seller is picking up premium for not much risk, it is bullish!!