A method of making an amorphous silica-alumina composition having: - a silica content of from 40 to 75 wt.% and an alumina content of from 25 to 60 wt.%, with the weight percent being based on the total dry weight of the silica-alumina composition; - less than 10 wt.% crystalline alumina; - an A/B ratio exceeding 2.2, wherein A in said ratio is the pore volume contained in pores of said composition having a pore diameter less than 2150 Å and B in said ratio is the pore volume contained in pores of said composition having a pore diameter of less than 210 Å, wherein the amorphous silica-alumina exhibits the characteristic of a penta-coordination peak in the NMR spectrum that has a relative size to the other aluminum peaks so as to represent the presence of penta-coordinated aluminum in an amount greater than 30 % of the total of the three types of aluminum, wherein said method comprises: forming within a mixing zone a precipitate solid comprising silica-alumina by: (a) introducing water into said mixing zone; (b) introducing aluminum sulfate into said mixing zone so as to provide a mixture comprising water and aluminum sulfate having a pH in the range of from 1.5 to 6.5; (c) thereafter, introducing sodium aluminate into said mixing zone to thereby increase the pH of said mixture to within the range of from 7.5 to 12 ( 'first pH swing'); (d) thereafter, introducing aluminum sulfate into said mixing zone to thereby lower the pH of said mixture to within the range of from 1.5 to 6.5; and (e) thereafter, introducing sodium silicate into said mixing zone to thereby increase the pH of said mixture to within the range of from 7.5 to 12 ( 'second pH swing'); and (f) after step (e), introducing aluminum sulfate into said mixing zone to thereby lower the pH of said mixture to within the range of from 1.5 to 6.5; (g) thereafter, introducing sodium aluminate into said mixing zone to thereby increase the pH of said mixture to within the range of from 7.5 to 12 ( 'third pH swing'); (h) thereafter, introducing aluminum sulfate into said mixing zone to thereby lower the pH of said mixture to within the range of from 1.5 to 6.5; and (i) thereafter, introducing sodium silicate into said mixing zone to thereby increase the pH of said mixture to within the range of from 7.5 to 12 ( 'fourth pH swing'); and recovering said precipitate solid from said mixture, wherein the mixture has a solids content of from 1 to 30 wt.% based on the total weight of the preparation mixture; wherein the mixing and reaction temperatures of each of the steps (b)-(i) are in the range of from 20 to 90°C; and wherein in the pH swings that involve the addition of aluminum sulfate followed by the addition of sodium aluminate, the weight ratio of the sodium aluminate-to-aluminum sulfate is from 0.1 to 1.5; wherein in the pH swings that involve the addition of aluminum sulfate followed by the addition of sodium silicate, the weight ratio of the sodium silicate-to-aluminum sulfate is from 0.5 to 5. - a silica content of from 40 to 75 wt.% and an alumina content of from 25 to 60 wt.%, with the weight percent being based on the total dry weight of the silica-alumina composition; - less than 10 wt.% crystalline alumina; - an A/B ratio exceeding 2.2, wherein A in said ratio is the pore volume contained in pores of said composition having a pore diameter less than 2150 Å and B in said ratio is the pore volume contained in pores of said composition having a pore diameter of less than 210 Å, (a) introducing water into said mixing zone; (b) introducing aluminum sulfate into said mixing zone so as to provide a mixture comprising water and aluminum sulfate having a pH in the range of from 1.5 to 6.5; (c) thereafter, introducing sodium aluminate into said mixing zone to thereby increase the pH of said mixture to within the range of from 7.5 to 12 ( 'first pH swing'); (d) thereafter, introducing aluminum sulfate into said mixing zone to thereby lower the pH of said mixture to within the range of from 1.5 to 6.5; and (e) thereafter, introducing sodium silicate into said mixing zone to thereby increase the pH of said mixture to within the range of from 7.5 to 12 ( 'second pH swing'); and (f) after step (e), introducing aluminum sulfate into said mixing zone to thereby lower the pH of said mixture to within the range of from 1.5 to 6.5; (g) thereafter, introducing sodium aluminate into said mixing zone to thereby increase the pH of said mixture to within the range of from 7.5 to 12 ( 'third pH swing'); (h) thereafter, introducing aluminum sulfate into said mixing zone to thereby lower the pH of said mixture to within the range of from 1.5 to 6.5; and (i) thereafter, introducing sodium silicate into said mixing zone to thereby increase the pH of said mixture to within the range of from 7.5 to 12 ( 'fourth pH swing'); and