Challenger bank OneSavings Bank saw its shares advance on its first day of dealing in London on Thursday after a less profitable initial public offer (IPO) than previously expected.A flotation price of 170p gave the bank a market value on flotation of £413m, short of the £500m-£600m range mooted a month earlier.The bank said it expected to raise roughly £134m gross, of which £41.5m would go to the bank and £93m to private equity owners JC Flowers. An over-allotment option could take the fundraising up to £154m if fully exercised, with all extra proceeds going to Flowers.Chief Executive Andy Golding said: "We are very pleased with the success of our IPO and with the strong support that we have seen for OSB's shares from top tier investors. "We are excited about the next phase of OSB's development and extremely confident that we have the right management and strategy in place to deliver long-term shareholder value, and a great customer proposition."The fundraising gives an impression of the support that could be given to the imminent IPO of TSB by parent Lloyds Banking Group later in the month.Later in 2014 and into 2015 there are expected flotations including Santander UK, Aldermore, Shawbrook, Virgin Money and Royal Bank of Scotland's Williams & Glynn business.OH