Faint hearts need not apply for a job shorting stocks, according to Ranger Capital, a US investment management boutique.

Scott Mason, president of Ranger Capital, said managers trying to short stocks for the first time found it hard to operate the discipline, which required an acute sense of timing. Losses were theoretically unlimited and the upward direction of the equity markets expected this year could make the risk of expensive failure greater. Fund managers were at risk of prime brokers recalling shares that had been lent to enable the short.