Source: Sharecast
Shares in Big Yellow soared last month when it emerged that the US private equity giant was in the early stages of considering a cash offer.
Under City rules, Blackstone - a global leader in commercial property investment - had until 1700 GMT on Monday to make a firm offer or walk away, a so-called put up or shut up deadline.
However, at the time Blackstone acknowledged it was considering various factors, including the macroeconomic environment and impact of the upcoming Budget on the self-storage sector.
Big Yellow said it had therefore asked, and received approval from, the Takeover Panel to extend the deadline to 1700 GMT on 8 December. Chancellor Rachel Reeves is due to present her Budget on 26 November.
In a brief statement, the firm reiterated: "There can be no certainty that a firm offer will be made for Big Yellow, nor to as to the terms on which any such firm offer might be made."
As at 0845 GMT, shares in Big Yellow - which have sparked 16% over the last month - were up nearly 1% at 1,126p.
The FTSE 250 firm currently has 110 stores, with a pipeline of 14 propose self-storage facilities.