AMMBid

[Source]

(Added by the AMM amendment)

Bid on an Automated Market Maker's (AMM's) auction slot. If you win, you can trade against the AMM at a discounted fee until you are outbid or 24 hours have passed. If you are outbid before 24 hours have passed, you are refunded part of the cost of your bid based on how much time remains. If the AMM's trading fee is zero, you can still bid, but the auction slot provides no benefit unless the trading fee changes.

You bid using the AMM's LP Tokens; the amount of a winning bid is returned to the AMM, decreasing the outstanding balance of LP Tokens.

Example AMMBid JSON

{
    "Account" : "rJVUeRqDFNs2xqA7ncVE6ZoAhPUoaJJSQm",
    "Asset" : {
        "currency" : "XRP"
    },
    "Asset2" : {
        "currency" : "TST",
        "issuer" : "rP9jPyP5kyvFRb6ZiRghAGw5u8SGAmU4bd"
    },
    "AuthAccounts" : [
        {
          "AuthAccount" : {
              "Account" : "rMKXGCbJ5d8LbrqthdG46q3f969MVK2Qeg"
          }
        },
        {
          "AuthAccount" : {
              "Account" : "rBepJuTLFJt3WmtLXYAxSjtBWAeQxVbncv"
          }
        }
    ],
    "BidMax" : {
        "currency" : "039C99CD9AB0B70B32ECDA51EAAE471625608EA2",
        "issuer" : "rE54zDvgnghAoPopCgvtiqWNq3dU5y836S",
        "value" : "100"
    },
    "Fee" : "10",
    "Flags" : 2147483648,
    "Sequence" : 9,
    "TransactionType" : "AMMBid"
}

AMMBid Fields

In addition to the common fields, AMMBid transactions use the following fields:

Auth Account Objects

Each member of the AuthAccounts array must be an object with the following field:

Like other "inner objects" that can appear in arrays, the JSON representation of each of these objects is wrapped in an object whose only key is the object type, AuthAccount.

Auction Slot Price

If successful, the transaction automatically outbids the previous slot owner and debits the bid price from the sender's LP Tokens. The price to win the auction decreases over time, divided into 20 intervals of 72 minutes each. If the sender does not have enough LP Tokens to win the bid, or the price of the bid is higher than the transaction's BidMax value, the transaction fails with a tecAMM_INVALID_TOKENS result.

• If the auction slot is currently empty, expired, or in its last interval, the minimum bid is defined by the following formula:

  M = L * F / 25
  

  • M is the minimum bid.
  • L is the total number of LP Tokens currently issued by the AMM
  • F is the trading fee, as a decimal

• Otherwise, the price to outbid the current holder is calculated using the following formula:

  P = B * 1.05 * (1 - t^60) + M
  

  • P is the price to outbid, in LP Tokens.
  • B is the price of the current bid, in LP Tokens.
  • t is the fraction of time elapsed in the current 24-hour slot, rounded down to a multiple of 0.05.
  • M is the minimum bid as defined above.

  There are two special cases for the cost to outbid someone. In the first interval after someone wins the bid, the price to outbid them is the minimum bid plus 5% more than the existing bid:

  P = B * 1.05 + M
  

  In the last interval of someone's slot, the cost to outbid someone is only the minimum bid:

  P = M
  

Bid Refunds

When you outbid an active auction slot, the AMM refunds the previous holder part of the price, using this formula:

R = B * (1 - t)

• R is the amount to refund, in LP Tokens.
• B is the price of the previous bid to be refunded, in LP Tokens.
• t is the fraction of time elapsed in the current 24-hour slot, rounded down to a multiple of 0.05.

As a special case, during the final (20th) interval of the auction slot, the refunded amount is zero.

Error Cases

Besides errors that can occur for all transactions, AMMBid transactions can result in the following transaction result codes: