Business-to-business e-commerce major Udaan has raised $120 million in convertible notes and debt from bondholders and shareholders said India’s largest business-to-business e-commerce company amid a funding winter for startups.

According to an internal company letter, the firm plans an IPO in the upcoming 12-18 months. In the last four quarters, the firm has crossed $350 million, making it one of the largest structured instrument fundraises countrywide.

B2B e-commerce firm Udaan’s existing investors include Lightspeed Venture Partners, Microsoft, Kaiser Permanente, M&G Prudential, Nomura, Arena Investors, TOR, Samena Capital, and Ishana Capital. Udaan valued $3.1 billion in its last funding round of $280 million in the first month of the previous year from existing and new investors.

Valuation for the latest funding would be done later – either during IPO or the pre-IPO funding round – the startup has raised the fund via a convertible note. A convertible note is instrument companies use during the pre-IPO stage to convert short-term debt into equities. Large-scale tech firms that have successfully used convertible notes include Uber, Airbnb, Robinhood, and Spotify.

As per the reports, Over the last year, Udaan has improved its unit economics by a total of over 1000bps with equally strong improvements in its gross margins and operating costs.