The actress arrived in the New York in July to appear on Broadway in the Arthur Miller play, All My Sons.
She is living in a Manhattan apartment owned by her husband Tom Cruise and has become a regular fixture on the city's social circuit.
As well as regularly frequenting the city's best restaurants, Holmes is often photographed with her daughter Suri carrying purchases from some of New York's most expensive shops.
The New York Post's Page Six magazine estimates that, mainly due to her real estate purchases, she has spent more than $14 million (£9.6 million) since being in the city.
"While ordinary city dwellers are cutting back, Mrs Cruise has been valiantly doing her bit to boost our economy," the magazine said.
"We tally up a conservative estimate of her 24-week NYC spending spree, and crown her Manhattan's Most Valued Shopper."
Holmes has reportedly spent a reported $13,987 (£9,600) on child care and taking Suri out over the last six months
According to the publication, she and Cruise have bought three new apartments in the building where he has owned his home since 1985.
A spokesperson for Cruise has denied the purchases but real estate executive Barbara Corcoran claims they bought a trio of lofts last year.
The magazine says a similar, three-bedroom home on the same street is on the market for $4.8 million, (£3.3 million) and calculates that the Cruises would have spent $14.4 million (£10 million) on their apartments as a result.
Meanwhile the couple is reported to have spent an additional $7,000 (£4,800) on installing gym equipment in their home.
The publication also claims that Holmes, 30, and Cruise, 46, have spent an estimated $7,315 (£5,000) on dining out at top restaurants such as brasserie Balthazar, and sushi restaurant Nobu and more than $17,000 (£11,700) on clothes for Holmes and Suri from shops like Hermes and Bonpoint.