Brokers will have until 5pm on 19 February to submit any decisions in principle and 5pm on 21 February to submit a full mortgage application, a statement on its website confirmed.
Applications must reach offer stage on or before 31 March.
“Any application not at offer stage at 5pm on 31 March will be cancelled, but regular updates will be provided throughout the process,” the lender said.
“We will look to lend on your application as normal and will contact you to confirm deadlines to submit documentation where required,” it added.
Extensions in exceptional circumstances
STB said extension requests would be considered “in exceptional circumstances on a case-by-case basis”, such as to allow for the completion of a chain or for delays in newly constructed properties.
For customers who have already paid a fee but may not be able to complete within the timescales, the lender said they should get in touch and try to assist them.
However, it added: “If we cannot, we will be happy to fully refund any valuation fees paid, provided the valuation has not been undertaken.”
Secure Trust Bank spent two years in the market after entering in March 2017, but last month announced it was consulting on a proposal to end its mortgage lending.
In its last interim report, published in August, Secure Trust said it had completed £37.3m total lending from its launch in 2017 to the end of June 2018, with £21.3m in the first six months of 2018.
Explaining the decision, the bank said: “The current economic climate, increased competition and continued uncertainties in the wider housing market have put the mortgage industry under huge pressure.
“These market pressures show no sign of abating, with competition intensifying as evidenced by increasing loan to value metrics and lower new lending margins.
“Having considered all of these factors, we have ceased origination of new mortgage lending until conditions become more favourable.”
It added that activities of other businesses within the Secure Trust Bank Group, including Commercial Finance and Real Estate Finance are unaffected.