Aug 12 (Reuters) - California weed supplier HERBL is in talks to go public by merging with blank check company BGP Acquisition, at a valuation of about $600 million, sources familiar with the matter said, one of several U.S. cannabis companies tapping funds in anticipation of potential federal reforms. Santa-Barbara, California-based HERBL, has seen its post-merger enterprise value cut to between $450 million and $500 million in recent weeks, from over $630 million in the original agreement reached with BGP around June, the sources said. That would translate to an equity valuation of about $600 million, down from around $800 million in the previous agreement, they added. BGP, a Special Purpose Acquisition Company (SPAC) formed by former Goldman Sachs banker Ruth Epstein, has been trying to raise roughly $50 million from investors as part of a so-called public investment in private equity (PIPE) round, they added. But it has been challenging for BGP to raise the money it needs to fund the deal at a high valuation, the sources said, so deal terms have been renegotiated to make them more attractive to potential investors. A PIPE is a funding round that typically goes hand-in-hand with a SPAC merger and helps provide necessary financing for such deals. By merging with BGP, HERBL’s shares will be listed on the NEO exchange in Canada, a country in which it does not do any business. There is no certainty that BGP will succeed in raising its PIPE funding or completing the deal, the sources cautioned, and HERBL could also decide to stay private. HERBL declined to comment, while BGP did not respond to Reuters’ requests. Sources declined to be identified because the discussions are confidential. (Reporting by Shariq Khan and Anirban Sen in Bengaluru Editing by Denny Thomas and David Gregorio)