OSLO (Reuters) - Norway’s largest bank DNB said on Monday it now holds a 90.9% stake in domestic rival Sbanken after additional shareholders accepted an improved voluntary offer. Last week, DNB raised its bid to 108.85 Norwegian crowns per share from 103.85 crowns, valuing the takeover at 11.6 billion Norwegian crowns ($1.39 billion). The planned takeover still remains subject to regulatory approval however. Based on preliminary calculations that were still subject to potential adjustments, DNB had received acceptances for a total of approximately 81% of shares in Sbanken at the expiry of the offer period at 1430 GMT, it said. Combined with existing holdings, DNB now holds approximately 90.9% in its rival, it added. Upon a successful completion DNB would proceed with a compulsory acquisition of the remaining shares in Sbanken. The takeover will increase DNB’s share of the Norwegian mortgage market to an estimated 27% from about 24% while also strengthening its asset management business. DNB was advised by in-house broker DNB Markets while Sbanken was advised by Arctic Securities. ($1 = 8.3240 Norwegian crowns) ($1 = 8.3237 Norwegian crowns) Reporting by Nora Buli, editing by Terje Solsvik Our Standards: The Thomson Reuters Trust Principles.