The challenger is raising £90m in new funds, and is selling a 25 per cent stake, plus an over-allotment option.
It follows stock market debuts from Aldermore earlier this month, and from Virgin Money in November.
Both of those flotations were delayed by choppy market conditions.
However, since then, investor sentiment towards the banks has improved – Virgin Money’s shares are up 41.7 per cent, and Aldermore’s have risen 13 per cent.
Combined with Shawbrook’s success, those figures illustrate the turnaround in market confidence in the past six months.
Joint global sponsors on the float were Bank of America Merrill Lynch and Goldman Sachs.