Eric Greitens, author and former Navy Seal, has yet to officially announce whether he’s seeking Missouri’s Republican nomination for governor in 2016.

But St. Louis-based Greitens already has collected at least $1.4 million in 2015 in large donations of more than $5,000 apiece. His largest monthly haul -- $540,000 – was in June.

So far this year, Greitens has been Missouri’s undisputedly biggest recipient of large donations.

Two of those June donations were $100,000 apiece from two East Coast hedge fund executives: Steven Cohen of Connecticut and James Parsons of New York.

Those big East Coast checks have the others in Missouri’s potential GOP field buzzing.

A spokesman said Greitens is delaying comment until the next campaign-finance reports are filed July 15. But those close to him expect Greitens – who has never run for office – to announce his bid for governor shortly.

His large June donations, in particular, swamped those of the announced or possible Republican rivals, including former House Speaker Catherine Hanaway, St. Louis businessman John Brunner and state Sen. Mike Parson of Bolivar. Hanaway received a single $750,000 contribution from retired financier Rex Sinquefield, but that was last year.

Greitens’ June tally even overshadowed the money-raising of the only major Democrat running for governor, Attorney General Chris Koster.

Chris Koster

Koster collected $340,000 in June in large donations of more than $5,000 apiece. Much of that money came from labor groups who see Koster as their best hope for blocking the continued GOP push to make Missouri a right-to-work state, which would significantly curb union clout.

Koster long has amassed far more cash than any of his GOP rivals, but his money-raising appeared to lag significantly in late 2014.

The fact that Greitens may have outraised Koster this spring could affect the Republican field, since some activists are looking for a candidate who can outmatch Koster dollar for dollar.