diff --git a/src/exch.c b/src/exch.c
index 6d1fba8..0c840a2 100644
--- a/src/exch.c
+++ b/src/exch.c
@@ -32,11 +32,222 @@
 #include "trader.h"
 
 
+/************************************************************************
+*                    Internal function declarations                     *
+************************************************************************/
+
+void visit_bank (void);
+void trade_shares (int num, bool *bid_used);
+
+
 /************************************************************************
 *                  Stock Exchange function definitions                  *
 ************************************************************************/
 
+/*-----------------------------------------------------------------------
+  Function:   exchange_stock  - Visit the Interstellar Stock Exchange
+  Arguments:  (none)
+  Returns:    (nothing)
+
+  This function allows the current player (in current_player) to buy,
+  sell and bid for shares in companies that appear on the galaxy map.
+*/
+
 void exchange_stock (void)
+{
+    selection_t selection = SEL_NONE;
+    bool bid_used = false;
+    bool all_off_map;
+    int i, line;
+
+
+    if (quit_selected || abort_game || ! player[current_player].in_game) {
+	return;
+    }
+
+    newtxwin(17, 80, LINE_OFFSET + 1, COL_CENTER(80));
+
+    while (selection != SEL_EXIT) {
+	selection = SEL_NONE;
+
+	// Display (or refresh) the Stock Exchange window
+	wbkgd(curwin, ATTR_NORMAL_WINDOW);
+	werase(curwin);
+	box(curwin, 0, 0);
+
+	center(curwin, 1, ATTR_WINDOW_TITLE, "  Interstellar Stock Exchange  ");
+	center2(curwin, 2, ATTR_NORMAL_WINDOW, ATTR_HIGHLIGHT_STR, "Player: ",
+		"%s", player[current_player].name);
+
+	all_off_map = true;
+	for (i = 0; i < MAX_COMPANIES; i++) {
+	    if (company[i].on_map) {
+		all_off_map = false;
+		break;
+	    }
+	}
+
+	if (all_off_map) {
+	    center(curwin, 8, ATTR_NORMAL_WINDOW, "No companies on the map");
+	} else {
+	    char *buf = malloc(BUFSIZE);
+	    if (buf == NULL) {
+		err_exit("out of memory");
+	    }
+
+	    // Handle the locale's currency symbol
+	    struct lconv *lc = localeconv();
+	    assert(lc != NULL);
+	    snprintf(buf, BUFSIZE, "share (%s)", lc->currency_symbol);
+
+	    wattrset(curwin, ATTR_WINDOW_SUBTITLE);
+	    mvwprintw(curwin, 4, 2, "  %-22s  %10s  %10s  %12s  %10s  ",
+		      "", "Shares", "Shares", "Price per", "");
+	    mvwprintw(curwin, 5, 2, "  %-22s  %10s  %10s  %12s  %10s  ",
+		      "Company", "issued", "left", buf, "Return (%)");
+	    wattrset(curwin, ATTR_NORMAL_WINDOW);
+
+	    for (line = 6, i = 0; i < MAX_COMPANIES; i++) {
+		if (company[i].on_map) {
+		    mvwaddch(curwin, line, 2, PRINTABLE_MAP_VAL(COMPANY_TO_MAP(i)) |
+			     ATTR_MAP_CHOICE);
+		    strfmon(buf, BUFSIZE, "%!12n", company[i].share_price);
+		    mvwprintw(curwin, line, 4, "%-22s  %'10ld  %'10ld  %12s  %10.2f  ",
+			      company[i].name, company[i].stock_issued,
+			      company[i].max_stock - company[i].stock_issued,
+			      buf, company[i].share_return * 100.0);
+		    line++;
+		}
+	    }
+
+	    free(buf);
+	}
+
+	wrefresh(curwin);
+
+	// Show menu of choices for the player
+	newtxwin(6, 80, LINE_OFFSET + 18, COL_CENTER(80));
+	wbkgd(curwin, ATTR_NORMAL_WINDOW);
+	box(curwin, 0, 0);
+
+	wmove(curwin, 3, 2);
+	attrpr(curwin, ATTR_KEYCODE_STR, "<1>");
+	waddstr(curwin, " Display stock portfolio");
+
+	wmove(curwin, 4, 2);
+	attrpr(curwin, ATTR_KEYCODE_STR, "<2>");
+	waddstr(curwin, " Display galaxy map");
+
+	wmove(curwin, 3, 40);
+	attrpr(curwin, ATTR_KEYCODE_STR, "<3>");
+	waddstr(curwin, " Visit the Trading Bank");
+
+	wmove(curwin, 4, 40);
+	attrpr(curwin, ATTR_KEYCODE_STR, "<4>");
+	waddstr(curwin, " Exit the Stock Exchange");
+
+	mvwaddstr(curwin, 1, 2, "                Enter selection ");
+	waddstr(curwin, "[");
+	attrpr(curwin, ATTR_HIGHLIGHT_STR, "Company letter");
+	waddstr(curwin, "/");
+	attrpr(curwin, ATTR_KEYCODE_STR, "1");
+	waddstr(curwin, "-");
+	attrpr(curwin, ATTR_KEYCODE_STR, "4");
+	waddstr(curwin, "]: ");
+
+	curs_set(CURS_ON);
+	wrefresh(curwin);
+
+	// Get the actual selection made by the player
+	while (selection == SEL_NONE) {
+	    int key = toupper(gettxchar(curwin));
+
+	    if (IS_COMPANY_KEY(key)) {
+		if (company[KEY_TO_COMPANY(key)].on_map) {
+		    selection = KEY_TO_COMPANY(key);
+		} else {
+		    beep();
+		}
+	    } else {
+		switch (key) {
+		case '1':
+		    curs_set(CURS_OFF);
+		    show_status(current_player);
+		    curs_set(CURS_ON);
+		    break;
+
+		case '2':
+		    curs_set(CURS_OFF);
+		    show_map(true);
+		    curs_set(CURS_ON);
+		    break;
+
+		case '3':
+		    selection = SEL_BANK;
+		    break;
+
+		case '4':
+		case ' ':
+		    selection = SEL_EXIT;
+		    break;
+
+		default:
+		    beep();
+		    break;
+		}
+	    }
+	}
+
+	curs_set(CURS_OFF);
+
+	deltxwin();		// "Enter selection" window
+	txrefresh();
+
+	if (selection == SEL_BANK) {
+	    // Visit the Interstellar Trading Bank
+	    visit_bank();
+	} else if (selection == SEL_EXIT) {
+	    // Exit the Stock Exchange: nothing more to do
+	    ;
+	} else {
+	    trade_shares(selection, &bid_used);
+	}
+    }
+
+    deltxwin();			// "Stock Exchange" window
+    txrefresh();
+}
+
+
+/*-----------------------------------------------------------------------
+  Function:   visit_bank  - Visit the Interstellar Trading Bank
+  Arguments:  (none)
+  Returns:    (nothing)
+
+  This function allows the current player to borrow or repay money from
+  the Interstellar Trading Bank.
+*/
+
+void visit_bank (void)
 {
     // @@@ To be written
 }
+
+
+/*-----------------------------------------------------------------------
+  Function:   trade_stock  - Trade stock in a particular company
+  Arguments:  num          - Company with which to trade
+              bid_used     - Has the player used up their bid?
+  Returns:    (nothing)
+
+  This function allows the current player to buy and sell stock in
+  company num.  The variable *bid_used is set to true if the player tries
+  to bid for more shares to be released by the company.
+*/
+
+void trade_shares (int num, bool *bid_used)
+{
+    assert(num >= 0 && num < MAX_COMPANIES);
+
+    // @@@ To be written
+}