By Walter Brandimarte

NEW YORK, July 9 (Reuters) - U.S.-listed shares of overseas companies dropped on Wednesday as concerns about a slowing global economy and potential new losses in the financial sector reduced investors' appetite for stocks in general.

The Bank of New York Mellon's index of leading American Depositary Receipts (ADRs) dropped 1.13 percent to its lowest level in almost three months as the Standard & Poor's 500 index .SPX fell into a bear market.

A further decline in oil prices weighed on the energy sector, while concerns about the economy put pressure on technology companies.

ADRs of Latin American companies posted the largest losses, with Bank of New York Mellon's index for the region dropping 2.2 percent.

Shares of Mexican mobile operator America Movil (AMX.N: Quote, Profile, Research) (AMXL.MX: Quote, Profile, Research) dragged on the market, sinking 3.69 percent to their lowest level in a year.

Investors were nervous about the upcoming release of America Movil's second-quarter results, which are expected to reveal whether the weakness seen in the first quarter was isolated or a sign of changing growth trends.

Shares of bellwether Brazilian oil company Petrobras (PBR.N: Quote, Profile, Research) (PETR4.SA: Quote, Profile, Research) lost 2.58 percent, marking the sixth consecutive session of losses on the New York Stock Exchange.

Asian ADRs followed suit, with losses of 1.47 percent according to the Bank of New York Mellon's index for the region .