In order to send files to an Amazon S3 bucket (either as a folder or as an export), the IAM policy attached to the key pair used is required to have the following permissions.

On the target bucket:

"Action": "s3:ListBucket" 

On any subfolders to be configured in the target bucket:

"Action": [
"s3:PutObject",
"s3:GetObject",
"s3:AbortMultipartUpload",
"s3:PutObjectVersionAcl",
"s3:PutObjectTagging",
"s3:PutObjectAcl",
"s3:ListMultipartUploadParts"
],

In addition, if it is desired to add the target bucket from a picklist (as opposed to entering the name manually), the key pair will need the s3:ListAllBuckets permission. However, this permission is NOT required in order to add a bucket or send files to it.