Blackstone Group, a buyout firm, and Wellcome Trust, a charitable trust in UK, decided to step out of the process of bidding for the branches of Royal Bank of Scotland, confirmed a source close to the matter.

Blackstone and Wellcome earlier made a consortium to make a joint bid for the branches of RBS.

The reason for the move was being told that the bid wasn't competitive enough. Now only four suitors are remaining for the branches of RBS. However, Blackstone and RBS declined to comment on the matter.

Blackstone and Wellcome took part in the first round of bids earlier this month. Reportedly they had to quit from the bidding process as RBS decided to shortlist the potential buyers. According to the reports, RBS is expected to complete this process of short listing as early as the start of May.

Royal Bank of Scotland, which is bailed out by the government in the time of financial crisis, expects to raise more than £1 billion by the selling of the branches. The on sale braches are of very importance for the companies as these branches would provide a foothold in banking for small and medium-sized companies.

Now, only four suitors are reportedly remaining for the 318 branches, being sold under the revived Williams & Glyn brand. The remaining bidders are Spanish lender Banco Santander, BBVA, National Australia Bank and Virgin Money. Among the bidders Banco Santander is widely seen as the front runner.