Adjusted EBITDA increased 537% year-on-year to US$33 million, which the company said was driven by higher sales volumes and per-unit profitability, partially offset by increased public company costs after the company started trading in New York in November.
It reported a realised price up 132% year-on-year to $5,891/t of rare earth oxide and a 13% rise in production costs to $1,475/t.
Revenue increased 189% to $60 million and adjusted net income rose 801% to $23.2 million compared with a year earlier.
The company produced 9,849t REO for the quarter from its Mountain Pass mine in California, 2% more than the previous corresponding period.
"Our solid first quarter results demonstrate our continued strong operational execution along with the upside our business has from higher rare earth prices," chairman and CEO James Litinsky said.
"Importantly, our Stage II optimisation plan is on track, and we are making steady progress on our Stage III vision."
The company, which currently sells its output to China-based circa 8% shareholder Shenghe Resources for further processing, did not provide more details on its plans to restore refining capabilities in the US.
MP Materials produced 38,503t REO in 2020, which it said was about 15% of the rare earth content consumed in the global market last year.
By comparison, ASX-listed Lynas Rare Earths said this month it currently supplied about 20% of world demand for separated rare earth products.
It produced 4,463t REO and 1,359t NdPr (neodymium and praseodymium) in the March quarter.
It has the Mt Weld mine in Western Australia, a processing plant in Malaysia and a plant under construction in WA.
Lynas also has an agreement with the US government to jointly fund the construction and development of a commercial Light Rare Earths separation plant in the US.
MP Materials last year said it had been awarded a Department of Defense grant to support detailed planning and design of a US-based Heavy Rare Earth separation facility.
It has said the construction of an HRE plant at Mountain Pass would be independent of but complementary to its stage two project.
MP shares (NYSE: MP) have risen from about $15 to peak above $51 in February.
They last traded at $27.69, valuing the company at $4.7 billion.
