Eton Park Capital Management, a New York hedge fund, disclosed in a regulatory filing that it had boosted its stake in Airgas Inc. to 7.27 percent, or six million shares, as of Friday, making it the second-largest shareholder in the Radnor industrial gases distributor behind company founder Peter McCausland.

Eton Park bought the Airgas shares after Air Products & Chemicals Inc. announced its $60-a-share buyout offer for Airgas, anticipating that Air Products will have to pay more.

Eton previously held 4.68 percent of Airgas' shares.

That growing numbers of shares are being held by Eton Park and other investors betting on a sale of Airgas, as opposed to shares being held by long-term investors, increases the pressure on Airgas' board to negotiate with suitors.    - Harold Brubaker