The stock climbed 33 percent to 114.75 pence (R19.58) a share, the highest since March 1.
The rand dropped 0.9 percent versus the dollar and has slid more than 9 percent since President Jacob Zuma ordered Finance Minister Pravin Gordhan home from a roadshow before firing him in a cabinet reshuffle.
Lonmin, which raised about $400 million (R5.48 billion) in a life-saving rights offer in 2015, burned through 70 percent of its cash in the final quarter of last year as a low platinum price combined with falling production from its biggest shaft.
The recent rand weakness makes further fundraising less likely, because it lowers the miner’s costs, said Arnold van Graan, a Johannesburg-based analyst at Nedbank Capital.
A basket of platinum group metals priced in rand, an indicator of Lonmin’s revenue, has climbed 11percent since March 24. The miner pays most of its costs in the local currency.
“Lonmin is the platinum stock most geared to the rand, so it’s been helped by recent weakness in the currency,” Van Graan said.
“As the rand-PGM basket price climbs, the cash burn should decrease, reducing the possible need for external funding.”
Short interest in the stock has steadily increased in the past few months, rising to 8.7 percent of shares outstanding as of Tuesday from 2.7 percent on January 31, according to data compiled by IHS Markit.
“The high level of short interest in the stock is creating additional volatilit,” Van Graan said.