Chinese investment in Brazil spiked in 2010 but has fallen since then, according to official data and independent studies, as executives grew frustrated with Brazil's slowing economy and protectionist policies.

Following are signs of how Chinese activity in Brazil has cooled in recent years:

However, official data only capture a fraction of the reality, since many Chinese companies invest in Brazil via subsidiaries based in the Caribbean or elsewhere.

A fuller study published in June by the China-Brazil Business Council (CBBC), a Rio de Janeiro-based group, included such ventures. It found that Chinese FDI in Brazil soared from $95 million in 2009 to a whopping $13.1 billion in 2010.

Since then, though, Chinese FDI in Brazil fell to $8 billion in 2011 and $2.8 billion in the first six months of 2012, the last period for which the CBBC tabulated such data.

The United States was officially the No. 1 source of FDI in Brazil in 2012, at $12.3 billion, and has also been the largest source so far this year.

The report attributed the drop to "uncertainties regarding Brazilian policies," highlighting recent changes to mining laws as well as new restrictions on how foreigners buy land.

"These and other related policies are ... causing companies to hold off investment plans," the CBBC said.

The study, which tabulated loans from Chinese banks, found that financing rose from $13.6 billion in 2009 to $37 billion in 2010. It then fell to $17.5 billion in 2011 and just $6.8 billion in 2012, the last year available.

(Reporting by Caroline Stauffer and Brian Winter; Editing by Kieran Murray and Ken Wills)