Tidal Bay has been allotted top weight of 11st 10lb in the John Smith's Grand National at Aintree on April 6.
The Paul Nicholls-trained 12-year-old has been in tremendous form this season, finishing second in the Hennessy at Newbury to Gold Cup favourite Bobs Worth and then winning the Lexus Chase at Leopardstown.
He has an official British Horseracing Authority mark of 171 but has been rated on 162 by official handicapper Phil Smith, who is allowed to use his discretion in framing the National weights.
Nicholls won the National for the first time last year when Neptune Collonges edged out Sunnyhillboy in a thrilling finish, and his team is further bolstered by Becher Chase runner-up Join Together (10st 12lb), and a pair part-owned by Sir Alex Ferguson in What A Friend (11st 5lb) and Harry The Viking (10st 2lb).
Tidal Bay is owned by Andrea and Graham Wylie, who also have leading contenders On His Own (10st 10lb) and Prince De Beauchene (11st 3lb), both of whom are trained by Willie Mullins in Ireland.
A strong Irish-trained entry of 31 features the Ted Walsh-trained pair of Seabass (11st 2lb) and Colbert Station (10st 11lb). Seabass carried 4lb less when third 12 months ago.
Colbert Station is owned by JP McManus and he also has Jonjo O'Neill's Sunnyhillboy, who has 11st this year compared to 10st 5lb in 2012, while the Donald McCain-trained Ballabriggs, successful in 2011, is another on 11st, the same weight as he carried to victory under Jason Maguire.
McCain said: "That weight is fine for Ballabriggs and it will be grand if the top horse (Tidal Bay) runs because then we will have a lovely racing weight.
"He has come out of his race at Warwick OK. He will go to Kelso for the Premier Chase, as he has done for the past two years, and then on to Aintree."
Betfred make Tidal Bay a 16-1 chance and spokesman Mark Pearson said: "Although no top-weight has won the National since Red Rum in 1974 the handicapper has definitely given him some leeway, and never underestimate the Paul Nicholls factor following his success in last year's race."
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