ETF Securities, the money-management firm that has made a name for itself as a purveyor of precious metals ETFs, filed with the Securities and Exchange Commission to expand the number of shares available for purchase on both its platinum and palladium ETFs amid robust demand for each.

With almost three-quarters of the already-registered shares of its platinum fund now sold, the company filed to raise the number of the ETFS Physical Platinum Shares ETF’s (NYSE Arca: PPLT) shares not yet purchased to 7.82 million. It first filed to offer 4.78 million. The new total includes 1.38 million shares from the first filing that have not yet sold.

The other filing, which adds new shares to its Physical Palladium Shares ETF (NYSE Arca: PALL), brings the number of unsold shares to 12.11 million. That figure includes 5.92 million shares registered for the first time. The company originally filed to sell 12.88, of which 6.19 million aren’t yet sold. That means half of the original amount has been sold. Both filings were dated April 23.

The platinum and palladium ETFs have been greeted with investor enthusiasm since both were launched in January. PPLT has hauled in about $564 million in assets while PALL has gathered $317 million.

Precious metals are in a bull market amid strong demand, particularly from Asia. PPLT has risen almost 10 percent since it was rolled out, settling Monday at $174.34 a share, while PALL has jumped almost 31 percent in the same period, closing today at $56.50 a share.

The company has offices in both New York and London.