The Wigan manager has consistently headed Sky Bet's market to replace Moyes, whose future has long been in doubt as he has failed to extend his contract, which expires this summer.
However, the Spaniard, whose current side are 1/4 for relegation, was backed into 1/2 for the post on Wednesday afternoon, with the current Toffees boss 1/12 to take the reins at Old Trafford following Ferguson's decision to retire this summer.
Jose Mourinho is the only other contender to be heavily supported to replace Ferguson but drifted back out from 11/10 to 7/1 on Wednesday afternoon, with a return to Stamford Bridge considered more likely as betting on him replacing Rafael Benitez was suspended earlier in the week.
Sky Bet Football Trader Chris Spicer said: "Moyes was marginal favourite for the post this morning as the news broke but has attracted the majority of the backing throughout the day, prompting his price to plummet and leading punters to turn their attentions to his replacement at Goodison Park.
"Martinez was already favourite at marginally odds-on and seems to be facing little opposition for the post, with Phil Neville his next closest contender at 10/1."