curl --request PATCH \
  --url https://api.treasuryprime.com/account/{account_id}/interest_rate \
  --header 'Authorization: Basic <encoded-value>' \
  --header 'Content-Type: application/json' \
  --data '{
  "interest_rate": 0.04
}'

{
  "account_number": "64141601",
  "account_type": "checking",
  "address": {
    "city": "San Francisco",
    "postal_code": "94104",
    "state": "CA",
    "street_line_1": "1 Market St",
    "street_line_2": "Suite 42"
  },
  "available_balance": "86753.09",
  "bank_id": "bank_treasuryprime",
  "business_ids": [],
  "created_at": "2017-11-02T11:55:14Z",
  "currency": "USD",
  "current_balance": "86753.09",
  "funded": true,
  "id": "acct_1029384756",
  "interest_rate": "0.04000",
  "lock": null,
  "locked": false,
  "name": "George Washington",
  "org_id": "org_1gwmpv3payf",
  "person_ids": [
    "owner_01d6y044p21s"
  ],
  "primary_person_id": "owner_01d6y044p21s",
  "routing_number": "021001208",
  "status": "open",
  "tags": null,
  "updated_at": "2017-11-02T11:55:14Z",
  "userdata": null
}