NOVELTY - Polymeric polyphosphite containing 2-1000 phosphate repeating units (A) and 0-1000 phosphate repeating units (B) is new.    USE - The polymeric polyphosphite is useful in a polymer composition (claimed), which is useful for: marine applications e.g. floating devices, pontoons, buoys, plastic lumber for decks, piers, boats, kayaks, oars, and beach reinforcements; automotive applications e.g. bumpers, dashboards, battery, rear and front linings; door panels; gas tank; glazing front side; rear windows; seat backing, exterior panels, wire insulation, profile extrusion for sealing, cladding, pillar covers, chassis parts, exhaust systems, fuel filter/filler, fuel pumps, fuel tank, body side moldings and sunroof; road traffic devices e.g. car accessories and warning triangles; devices for plane and railway; devices for space applications, preferably rockets and satellites; devices for architecture and design, mining applications, acoustic quietized systems, street refuges, and shelters; appliances, cases and coverings in general and electric/electronic devices (personal computer, telephone, portable phone, printer, TV-sets, audio and video devices), flower pots, satellite TV bowl, and panel devices; jacketing for other materials such as steel or textiles; devices for the electronic industry, preferably insulation for computer plugs, cases for electric and electronic parts, printed boards, and materials for electronic data storage such as chips, check cards or credit cards; electric appliances, preferably washing machines, tumblers, ovens (microwave oven), dish-washers, mixers, and irons; covers for lights (e.g. street-lights); applications in wire and cable (semi-conductor, insulation and cable-jacketing); foils for e.g. condensers, refrigerators, coffee machines, and vacuum cleaners; technical articles e.g. cogwheel (gear), screws, bolts, handles, and knobs; rotor blades, ventilators and windmill vanes, solar devices, swimming pools, swimming pool covers, pool liners, pond liners, closets, wardrobes, dividing walls, slat walls, folding walls, roofs, shutters (e.g. roller shutters), fittings, connections between pipes, sleeves, and conveyor belts; sanitary articles, preferably shower cubicles, lavatory seats, covers, and sinks; hygienic articles e.g. diapers, feminine hygiene articles and brushes; pipes (crosslinked or not) for e.g. water, waste water and chemicals, and drainage systems; profiles of any geometry (window panes) and siding; glass substitutes e.g. extruded or co-extruded plates and window film for architectural glazing; plates (walls and cutting board); extrusion coating (photographic paper and pipe coating), silos, wood substitute, plastic lumber, wood composites, walls, surfaces, furniture and decorative foil; floor coverings (interior and exterior applications); duck boards; tiles; intake and outlet manifolds; cement-, concrete-, composite-applications and covers, siding and cladding, hand rails, banisters, kitchen work tops, roofing, roofing sheets, tiles, and tarpaulins; artificial covering for stadium rings (athletics); fibers (carpets/hygienic articles/geotextiles/monofilaments); filters; wipes/curtains (shades/medical applications), bulk fibers (applications such as gown/protection clothes), nets, ropes, cables, strings, cords, threads, safety seat-belts, clothes, underwear and gloves; rubber boots; intimate apparel; swimwear; sportswear; umbrellas; parachutes; paraglides; sails; balloon-silk; camping articles; tents; airbeds; sun beds; bulk bags; covers and seals for roofs, tunnels, dumps, ponds, dumps, walls roofing membranes, awnings, canopies, wallpaper, food packing and wrapping (flexible and solid), dashboard, cockpits and door; films (packaging, dump, laminating, agriculture and horticulture, greenhouse, mulch, tunnel and silage), bale wrap, swimming pools, waste bags, wallpaper, stretch film, raffia, desalination film, batteries, and connectors; storage systems such as boxes (crates), luggage, chest, household boxes, pallets, shelves, tracks, screw boxes, packs, and cans; cartridges, syringes, medical applications, containers for any transportation, waste baskets and waste bins, dust bins, bin liners, wheelie bins and tanks for water/used water/chemistry/gas/oil/gasoline/diesel; tank liners, boxes, crates, battery cases, troughs, medical devices such as piston, ophthalmic applications, diagnostic devices, and packing for pharmaceuticals blister; support devices, articles for the leisure time such as sports and fitness devices, gymnastics mats, ski-boots, inline-skates, skis, big foot, and athletic surfaces (e.g. tennis grounds); screw tops, tops and stoppers for bottles, and cans; furniture e.g. foamed articles and stadium seats; materials for optical and magnetic data storage; kitchen ware; boxes for cassettes and video tapes; DVD electronic articles; adhesive tapes; footwear (shoes/shoe-soles); structural adhesives; food boxes (fruit, vegetables, meat and fish); synthetic paper; labels for bottles, couches, artificial joints (human), printing plates (flexographic), printed circuit boards, and display technologies; and devices of filled polymers (talc, chalk, china clay (kaolin), wollastonite, pigments, carbon black, titanium dioxide, mica, nanocomposites, dolomite, silicates, glass, asbestos).    ADVANTAGE - The polymeric polyphosphite has increased hydrolytic stability and resistance to migration in food packaging and excellent compatibility, imparts excellent color stability, increases thermal stabilization in PVC, and reduces the yellowness index of the synthetic polymer.    DETAILED DESCRIPTION - Polymeric polyphosphite containing 2-1000 phosphate repeating units of formula (A) and 0-1000 phosphate repeating units of formula (B) is new.    R2=1-20C-alky, 2-22C-alkenyl, 2-20C-polyalkylene glycol chain, or 3-7 membered ring containing -CO-O- group;    R7, R9=1-6C-alkylene;    R8=5-10 saturated carbocyclic rings;    a, b=0-1;    Y1=2-22C-alkylene;    m=1-20; and    R1, R3, R4=R2, where the polyphosphite is terminated adjacent to the -P(OR2)- group of the formula above by R1O-, and terminated at the other end of the chain by -P(OR3)(OR4).    Provided that when the polyphosphite contains 1-12 units of (B), it must contain 2 or more units of (A), and further provided that when the polyphosphite contains no units of (B), it must contain 8 or more units of (A). INDEPENDENT CLAIMS are included for:    (1) the preparation of the polymeric polyphosphite; and    (2) a polymer composition comprising a synthetic polymer, and the polymeric polyphosphite.