Capital market regulator on Friday approved digital payments firm MobiKwik's plan to launch an initial public offering (IPO) of shares worth up to Rs 1,900 crore ($253.41 million), a source directly aware of the matter said.The IPO includes the issue of new shares worth Rs 1,500 crore and an offer for sale of shares worth up to Rs 400 crore, diluting the stakes of its two founders and current investors including Sequoia Capital, Bajaj Finance and also include American Express.MobiKwik did not immediately respond to a request for comment.